Revert "Kill Jemalloc"

This reverts commit e03f7dc885.

FindJeMalloc.cmake

@@ -0,0 +1,44 @@
+# - Try to find jemalloc headers and libraries.
+#
+# Usage of this module as follows:
+#
+#     find_package(JeMalloc)
+#
+# Variables used by this module, they can change the default behaviour and need
+# to be set before calling find_package:
+#
+#  JEMALLOC_ROOT_DIR Set this variable to the root installation of
+#                    jemalloc if the module has problems finding
+#                    the proper installation path.
+#
+# Variables defined by this module:
+#
+#  JEMALLOC_FOUND             System has jemalloc libs/headers
+#  JEMALLOC_LIBRARIES         The jemalloc library/libraries
+#  JEMALLOC_INCLUDE_DIR       The location of jemalloc headers
+
+find_path(JEMALLOC_ROOT_DIR
+    NAMES include/jemalloc/jemalloc.h
+)
+
+find_library(JEMALLOC_LIBRARIES
+    NAMES jemalloc
+    HINTS ${JEMALLOC_ROOT_DIR}/lib
+)
+
+find_path(JEMALLOC_INCLUDE_DIR
+    NAMES jemalloc/jemalloc.h
+    HINTS ${JEMALLOC_ROOT_DIR}/include
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(JeMalloc DEFAULT_MSG
+    JEMALLOC_LIBRARIES
+    JEMALLOC_INCLUDE_DIR
+)
+
+mark_as_advanced(
+    JEMALLOC_ROOT_DIR
+    JEMALLOC_LIBRARIES
+    JEMALLOC_INCLUDE_DIR
+)