cmake: add LIBSSH2_DISABLE_INSTALL option

To disable all installation targets.

Closes #1638

CMakeLists.txt

@@ -172,12 +172,15 @@ if(NOT LIBSSH2_VERSION OR
   message(FATAL_ERROR "Unable to parse version from ${PROJECT_SOURCE_DIR}/include/libssh2.h")
 endif()
 
+option(LIBSSH2_DISABLE_INSTALL "Disable installation targets" OFF)
+if(NOT LIBSSH2_DISABLE_INSTALL)
   include(GNUInstallDirs)
   install(
     FILES
       COPYING NEWS README RELEASE-NOTES
       docs/AUTHORS docs/BINDINGS.md docs/HACKING.md
     DESTINATION ${CMAKE_INSTALL_DOCDIR})
+endif()
 
 include(PickyWarnings)
 

docs/CMakeLists.txt

@@ -40,5 +40,7 @@ libssh2_transform_makefile_inc("Makefile.am" "${CMAKE_CURRENT_BINARY_DIR}/Makefi
 # Get dist_man_MANS variable
 include("${CMAKE_CURRENT_BINARY_DIR}/Makefile.am.cmake")
 
+if(NOT LIBSSH2_DISABLE_INSTALL)
   include(GNUInstallDirs)
   install(FILES ${dist_man_MANS} DESTINATION "${CMAKE_INSTALL_MANDIR}/man3")
+endif()

src/CMakeLists.txt

@@ -177,6 +177,7 @@ add_library(${LIB_NAME} ALIAS ${LIB_SELECTED})
 
 ## Installation
 
+if(NOT LIBSSH2_DISABLE_INSTALL)
   install(FILES
     "${PROJECT_SOURCE_DIR}/include/libssh2.h"
     "${PROJECT_SOURCE_DIR}/include/libssh2_publickey.h"
@@ -405,3 +406,4 @@ write_basic_package_version_file(
   install(
     FILES "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-config-version.cmake"
     DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
+endif()