cmake: add support for missing SOVERSION (#919)

Summary:
Closes: https://github.com/facebookresearch/fastText/issues/918
Pull Request resolved: https://github.com/facebookresearch/fastText/pull/919

Reviewed By: EdouardGrave, tscmoo

Differential Revision: D17737704

Pulled By: Celebio

fbshipit-source-id: 3bc0c4825917017d4f98fa4c8c3f1af2a0c8c31f

CMakeLists.txt

@@ -52,7 +52,8 @@ set(SOURCE_FILES
 add_library(fasttext-shared SHARED ${SOURCE_FILES} ${HEADER_FILES})
 add_library(fasttext-static STATIC ${SOURCE_FILES} ${HEADER_FILES})
 add_library(fasttext-static_pic STATIC ${SOURCE_FILES} ${HEADER_FILES})
-set_target_properties(fasttext-shared PROPERTIES OUTPUT_NAME fasttext)
+set_target_properties(fasttext-shared PROPERTIES OUTPUT_NAME fasttext
+  SOVERSION "${fasttext_VERSION_MAJOR}")
 set_target_properties(fasttext-static PROPERTIES OUTPUT_NAME fasttext)
 set_target_properties(fasttext-static_pic PROPERTIES OUTPUT_NAME fasttext_pic
   POSITION_INDEPENDENT_CODE True)