diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7ad75ece..ac2ae892 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,6 +61,54 @@ function(libssh2_dumpvars)  # Dump all defined variables with their values
   message("::endgroup::")
 endfunction()
 
+set(_target_flags "")
+if(APPLE)
+  set(_target_flags "${_target_flags} APPLE")
+endif()
+if(UNIX)
+  set(_target_flags "${_target_flags} UNIX")
+endif()
+if(BSD)
+  set(_target_flags "${_target_flags} BSD")
+endif()
+if(ANDROID)
+  set(_target_flags "${_target_flags} ANDROID-${ANDROID_PLATFORM_LEVEL}")
+endif()
+if(WIN32)
+  set(_target_flags "${_target_flags} WIN32")
+endif()
+if(WINDOWS_STORE)
+  set(_target_flags "${_target_flags} UWP")
+endif()
+if(CYGWIN)
+  set(_target_flags "${_target_flags} CYGWIN")
+endif()
+if(MSYS)
+  set(_target_flags "${_target_flags} MSYS")
+endif()
+if(DOS)
+  set(_target_flags "${_target_flags} DOS")
+endif()
+if(AMIGA)
+  set(_target_flags "${_target_flags} AMIGA")
+endif()
+if(CMAKE_COMPILER_IS_GNUCC)
+  set(_target_flags "${_target_flags} GCC")
+endif()
+if(MINGW)
+  set(_target_flags "${_target_flags} MINGW")
+endif()
+if(MSVC)
+  set(_target_flags "${_target_flags} MSVC-${MSVC_VERSION}")
+endif()
+if(VCPKG_TOOLCHAIN)
+  set(_target_flags "${_target_flags} VCPKG")
+endif()
+if(CMAKE_CROSSCOMPILING)
+  set(_target_flags "${_target_flags} CROSS")
+endif()
+message(STATUS "CMake platform flags:${_target_flags}")
+
 if(NOT DEFINED CMAKE_UNITY_BUILD_BATCH_SIZE)
   set(CMAKE_UNITY_BUILD_BATCH_SIZE 0)
 endif()
@@ -139,6 +187,16 @@ else()
   set(LIB_SELECTED ${LIB_STATIC})
 endif()
 
+# Override to force-disable or force-enable the use of pkg-config.
+if((UNIX AND NOT ANDROID AND (NOT APPLE OR CMAKE_SYSTEM_NAME MATCHES "Darwin")) OR
+   VCPKG_TOOLCHAIN OR
+   (MINGW AND NOT CMAKE_CROSSCOMPILING))
+  set(_libssh2_use_pkgconfig_default ON)
+else()
+  set(_libssh2_use_pkgconfig_default OFF)
+endif()
+option(LIBSSH2_USE_PKGCONFIG "Enable pkg-config to detect dependencies" ${_libssh2_use_pkgconfig_default})
+
 # Symbol hiding
 
 option(HIDE_SYMBOLS "Hide all libssh2 symbols that are not officially external" ON)
@@ -357,7 +415,7 @@ if(CRYPTO_BACKEND STREQUAL "wolfSSL" OR NOT CRYPTO_BACKEND)
     set(CRYPTO_BACKEND_INCLUDE_DIR ${WOLFSSL_INCLUDE_DIRS})
     list(APPEND LIBSSH2_LIBS ${WOLFSSL_LIBRARIES})
     list(APPEND LIBSSH2_LIBDIRS ${WOLFSSL_LIBRARY_DIRS})
-    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE "wolfssl")
+    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE ${WOLFSSL_PC_REQUIRES})
     link_directories(${WOLFSSL_LIBRARY_DIRS})
     if(WOLFSSL_CFLAGS)
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WOLFSSL_CFLAGS}")
@@ -386,7 +444,7 @@ if(CRYPTO_BACKEND STREQUAL "Libgcrypt" OR NOT CRYPTO_BACKEND)
     set(CRYPTO_BACKEND_INCLUDE_DIR ${LIBGCRYPT_INCLUDE_DIRS})
     list(APPEND LIBSSH2_LIBS ${LIBGCRYPT_LIBRARIES})
     list(APPEND LIBSSH2_LIBDIRS ${LIBGCRYPT_LIBRARY_DIRS})
-    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE "libgcrypt")
+    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE ${LIBGCRYPT_PC_REQUIRES})
     link_directories(${LIBGCRYPT_LIBRARY_DIRS})
     if(LIBGCRYPT_CFLAGS)
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${LIBGCRYPT_CFLAGS}")
@@ -404,7 +462,7 @@ if(CRYPTO_BACKEND STREQUAL "mbedTLS" OR NOT CRYPTO_BACKEND)
     set(CRYPTO_BACKEND_INCLUDE_DIR ${MBEDTLS_INCLUDE_DIRS})
     list(APPEND LIBSSH2_LIBS ${MBEDTLS_LIBRARIES})
     list(APPEND LIBSSH2_LIBDIRS ${MBEDTLS_LIBRARY_DIRS})
-    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE "mbedcrypto")
+    list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE ${MBEDTLS_PC_REQUIRES})
     link_directories(${MBEDTLS_LIBRARY_DIRS})
     if(MBEDTLS_CFLAGS)
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${MBEDTLS_CFLAGS}")
diff --git a/cmake/FindLibgcrypt.cmake b/cmake/FindLibgcrypt.cmake
index f6fc5f7a..2ec3cfa2 100644
--- a/cmake/FindLibgcrypt.cmake
+++ b/cmake/FindLibgcrypt.cmake
@@ -15,14 +15,17 @@
 # - `LIBGCRYPT_INCLUDE_DIRS`:  The Libgcrypt include directories.
 # - `LIBGCRYPT_LIBRARIES`:     The Libgcrypt library names.
 # - `LIBGCRYPT_LIBRARY_DIRS`:  The Libgcrypt library directories.
+# - `LIBGCRYPT_PC_REQUIRES`:   The Libgcrypt pkg-config packages.
 # - `LIBGCRYPT_CFLAGS`:        Required compiler flags.
 # - `LIBGCRYPT_VERSION`:       Version of Libgcrypt.
 
-if((UNIX OR VCPKG_TOOLCHAIN OR (MINGW AND NOT CMAKE_CROSSCOMPILING)) AND
+set(LIBGCRYPT_PC_REQUIRES "libgcrypt")
+
+if(LIBSSH2_USE_PKGCONFIG AND
    NOT DEFINED LIBGCRYPT_INCLUDE_DIR AND
    NOT DEFINED LIBGCRYPT_LIBRARY)
   find_package(PkgConfig QUIET)
-  pkg_check_modules(LIBGCRYPT "libgcrypt")
+  pkg_check_modules(LIBGCRYPT ${LIBGCRYPT_PC_REQUIRES})
 endif()
 
 if(LIBGCRYPT_FOUND)
diff --git a/cmake/FindMbedTLS.cmake b/cmake/FindMbedTLS.cmake
index ac105019..edfcec1f 100644
--- a/cmake/FindMbedTLS.cmake
+++ b/cmake/FindMbedTLS.cmake
@@ -15,20 +15,25 @@
 # - `MBEDTLS_INCLUDE_DIRS`:  The mbedTLS include directories.
 # - `MBEDTLS_LIBRARIES`:     The mbedTLS library names.
 # - `MBEDTLS_LIBRARY_DIRS`:  The mbedTLS library directories.
+# - `MBEDTLS_PC_REQUIRES`:   The mbedTLS pkg-config packages.
 # - `MBEDTLS_CFLAGS`:        Required compiler flags.
 # - `MBEDTLS_VERSION`:       Version of mbedTLS.
 
-if((UNIX OR VCPKG_TOOLCHAIN OR (MINGW AND NOT CMAKE_CROSSCOMPILING)) AND
+set(MBEDTLS_PC_REQUIRES "mbedcrypto")
+
+if(LIBSSH2_USE_PKGCONFIG AND
    NOT DEFINED MBEDTLS_INCLUDE_DIR AND
    NOT DEFINED MBEDCRYPTO_LIBRARY)
   find_package(PkgConfig QUIET)
-  pkg_check_modules(MBEDTLS "mbedcrypto")
+  pkg_check_modules(MBEDTLS ${MBEDTLS_PC_REQUIRES})
 endif()
 
 if(MBEDTLS_FOUND)
   string(REPLACE ";" " " MBEDTLS_CFLAGS "${MBEDTLS_CFLAGS}")
   message(STATUS "Found MbedTLS (via pkg-config): ${MBEDTLS_INCLUDE_DIRS} (found version \"${MBEDTLS_VERSION}\")")
 else()
+  set(MBEDTLS_PC_REQUIRES "")
+
   find_path(MBEDTLS_INCLUDE_DIR NAMES "mbedtls/version.h")
   find_library(MBEDCRYPTO_LIBRARY NAMES "mbedcrypto" "libmbedcrypto")
 
diff --git a/cmake/FindWolfSSL.cmake b/cmake/FindWolfSSL.cmake
index 31ddd303..9791b62c 100644
--- a/cmake/FindWolfSSL.cmake
+++ b/cmake/FindWolfSSL.cmake
@@ -15,14 +15,17 @@
 # - `WOLFSSL_INCLUDE_DIRS`:  The wolfSSL include directories.
 # - `WOLFSSL_LIBRARIES`:     The wolfSSL library names.
 # - `WOLFSSL_LIBRARY_DIRS`:  The wolfSSL library directories.
+# - `WOLFSSL_PC_REQUIRES`:   The wolfSSL pkg-config packages.
 # - `WOLFSSL_CFLAGS`:        Required compiler flags.
 # - `WOLFSSL_VERSION`:       Version of wolfSSL.
 
-if((UNIX OR VCPKG_TOOLCHAIN OR (MINGW AND NOT CMAKE_CROSSCOMPILING)) AND
+set(WOLFSSL_PC_REQUIRES "wolfssl")
+
+if(LIBSSH2_USE_PKGCONFIG AND
    NOT DEFINED WOLFSSL_INCLUDE_DIR AND
    NOT DEFINED WOLFSSL_LIBRARY)
   find_package(PkgConfig QUIET)
-  pkg_check_modules(WOLFSSL "wolfssl")
+  pkg_check_modules(WOLFSSL ${WOLFSSL_PC_REQUIRES})
 endif()
 
 if(WOLFSSL_FOUND)
diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt
index a5b0980c..a35699fb 100644
--- a/example/CMakeLists.txt
+++ b/example/CMakeLists.txt
@@ -49,8 +49,8 @@ foreach(_example IN LISTS noinst_PROGRAMS)
   list(APPEND _example_targets ${_example})
   # to find generated header
   target_include_directories(${_example} PRIVATE
-    "${CMAKE_CURRENT_BINARY_DIR}/../src"
-    "../src")
+    "${PROJECT_BINARY_DIR}/src"
+    "${PROJECT_SOURCE_DIR}/src")
   target_link_libraries(${_example} ${LIB_SELECTED} ${LIBSSH2_LIBS})
   set_target_properties(${_example} PROPERTIES UNITY_BUILD OFF)
 endforeach()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 16de683a..0d3c5be2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -40,8 +40,6 @@ set(_libssh2_soversion 1)
 set(_libssh2_libversion 1.0.1)
 
 if(CRYPTO_BACKEND)
-  list(APPEND PRIVATE_COMPILE_DEFINITIONS ${CRYPTO_BACKEND_DEFINE})
-  list(APPEND PRIVATE_INCLUDE_DIRECTORIES ${CRYPTO_BACKEND_INCLUDE_DIR})
   add_feature_info("Crypto backend" ON "${CRYPTO_BACKEND}")
 else()
   message(FATAL_ERROR "No suitable cryptography backend found.")
@@ -62,18 +60,17 @@ add_feature_info(Compression ENABLE_ZLIB_COMPRESSION
 if(ENABLE_ZLIB_COMPRESSION)
   find_package(ZLIB REQUIRED)
 
-  list(APPEND libssh2_INCLUDE_DIRS ${ZLIB_INCLUDE_DIRS})
   list(APPEND LIBSSH2_LIBS ${ZLIB_LIBRARIES})
   list(APPEND LIBSSH2_PC_REQUIRES_PRIVATE "zlib")
+  include_directories(SYSTEM ${ZLIB_INCLUDE_DIRS})
   if(ZLIB_FOUND)
     list(APPEND _libssh2_definitions "LIBSSH2_HAVE_ZLIB")
   endif()
 endif()
 
-list(APPEND LIBSSH2_LIBS ${LIBSSH2_LIBS_SOCKET})
+include_directories(SYSTEM ${CRYPTO_BACKEND_INCLUDE_DIR})
 
-# to find generated header
-list(APPEND libssh2_INCLUDE_DIRS ${CMAKE_CURRENT_BINARY_DIR})
+list(APPEND LIBSSH2_LIBS ${LIBSSH2_LIBS_SOCKET})
 
 if(MSVC)
   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -Zi -Od")
@@ -109,7 +106,7 @@ if(BUILD_STATIC_LIBS OR BUILD_STATIC_FOR_TESTS)
   endif()
   add_library(${LIB_STATIC} STATIC ${_sources})
   add_library(${PROJECT_NAME}::${LIB_STATIC} ALIAS ${LIB_STATIC})
-  target_compile_definitions(${LIB_STATIC} PRIVATE ${PRIVATE_COMPILE_DEFINITIONS} ${_libssh2_definitions})
+  target_compile_definitions(${LIB_STATIC} PRIVATE ${CRYPTO_BACKEND_DEFINE} ${_libssh2_definitions})
   target_link_libraries(${LIB_STATIC} PRIVATE ${LIBSSH2_LIBS})
   set_target_properties(${LIB_STATIC} PROPERTIES
     PREFIX "" OUTPUT_NAME "libssh2" SOVERSION "${_libssh2_soversion}" VERSION "${_libssh2_libversion}"
@@ -117,9 +114,8 @@ if(BUILD_STATIC_LIBS OR BUILD_STATIC_FOR_TESTS)
 
   target_include_directories(${LIB_STATIC}
     PRIVATE
+      "${CMAKE_CURRENT_BINARY_DIR}"    # to find generated header
       "${PROJECT_SOURCE_DIR}/include"
-      ${libssh2_INCLUDE_DIRS}
-      ${PRIVATE_INCLUDE_DIRECTORIES}
     PUBLIC
       "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>"
       "$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${CMAKE_INSTALL_INCLUDEDIR}>")
@@ -131,7 +127,7 @@ if(BUILD_SHARED_LIBS)
   if(WIN32)
     set_property(TARGET ${LIB_SHARED} APPEND PROPERTY SOURCES "libssh2.rc")
   endif()
-  target_compile_definitions(${LIB_SHARED} PRIVATE ${PRIVATE_COMPILE_DEFINITIONS} ${_libssh2_definitions} ${LIB_SHARED_DEFINITIONS})
+  target_compile_definitions(${LIB_SHARED} PRIVATE ${CRYPTO_BACKEND_DEFINE} ${_libssh2_definitions} ${LIB_SHARED_DEFINITIONS})
   target_compile_options(${LIB_SHARED} PRIVATE ${LIB_SHARED_C_FLAGS})
   target_link_libraries(${LIB_SHARED} PRIVATE ${LIBSSH2_LIBS})
   set_target_properties(${LIB_SHARED} PROPERTIES
@@ -141,9 +137,8 @@ if(BUILD_SHARED_LIBS)
 
   target_include_directories(${LIB_SHARED}
     PRIVATE
+      "${CMAKE_CURRENT_BINARY_DIR}"    # to find generated header
       "${PROJECT_SOURCE_DIR}/include"
-      ${libssh2_INCLUDE_DIRS}
-      ${PRIVATE_INCLUDE_DIRECTORIES}
     PUBLIC
       "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>"
       "$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/${CMAKE_INSTALL_INCLUDEDIR}>")
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 80c942e2..e0be403a 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -38,6 +38,8 @@
 
 include(CopyRuntimeDependencies)
 
+include_directories(SYSTEM ${CRYPTO_BACKEND_INCLUDE_DIR})
+
 list(APPEND LIBSSH2_LIBS ${LIBSSH2_LIBS_SOCKET})
 
 transform_makefile_inc("Makefile.inc" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
@@ -73,10 +75,9 @@ endif()
 add_library(runner STATIC ${librunner_la_SOURCES})
 target_compile_definitions(runner PRIVATE "${CRYPTO_BACKEND_DEFINE}")
 target_include_directories(runner PRIVATE
-  "${CMAKE_CURRENT_BINARY_DIR}/../src"
-  "../src"
-  "../include"
-  "${CRYPTO_BACKEND_INCLUDE_DIR}")
+  "${PROJECT_BINARY_DIR}/src"
+  "${PROJECT_SOURCE_DIR}/src"
+  "${PROJECT_SOURCE_DIR}/include")
 target_link_libraries(runner PRIVATE libssh2)
 
 foreach(_test IN LISTS DOCKER_TESTS STANDALONE_TESTS SSHD_TESTS)
@@ -95,10 +96,9 @@ foreach(_test IN LISTS DOCKER_TESTS STANDALONE_TESTS SSHD_TESTS)
     add_executable(${_test} "${_test}.c")
     target_compile_definitions(${_test} PRIVATE "${CRYPTO_BACKEND_DEFINE}")
     target_include_directories(${_test} PRIVATE
-      "${CMAKE_CURRENT_BINARY_DIR}/../src"
-      "../src"
-      "../include"
-      "${CRYPTO_BACKEND_INCLUDE_DIR}")
+      "${PROJECT_BINARY_DIR}/src"
+      "${PROJECT_SOURCE_DIR}/src"
+      "${PROJECT_SOURCE_DIR}/include")
     set_target_properties(${_test} PROPERTIES UNITY_BUILD OFF)
 
     # build a single test with gcov