Fix generation of git_version.h

The file does not get cleaned up, thus this file eventually contains
mulitiple versions.

Signed-off-by: Maud Spierings <maud_spierings@hotmail.com>

Author: SpieringsAE

wrapper/CMakeLists.txt

@@ -43,7 +43,7 @@ if (WIN32)
 add_custom_command(
     OUTPUT ${gitversion_h}
     COMMAND ${CMAKE_COMMAND} -E make_directory ${generated_files_dir}
-    COMMAND ${CMAKE_COMMAND} -E echo "#define GIT_VERSION \"${version}\"" >> ${gitversion_h};
+    COMMAND ${CMAKE_COMMAND} -E echo "#define GIT_VERSION \"${version}\"" > ${gitversion_h};
     COMMAND ${CMAKE_COMMAND} -E echo "#define PLATFORM_WINDOWS 1" >> ${gitversion_h}
     COMMAND ${CMAKE_COMMAND} -E echo "#define ENABLE_LOGGING 1" >> ${gitversion_h}
     COMMAND ${CMAKE_COMMAND} -E echo "#define DEFAULT_VISIBILITY /**/" >> ${gitversion_h}
@@ -54,7 +54,7 @@ else ()
 add_custom_command(
     OUTPUT ${gitversion_h}
     COMMAND ${CMAKE_COMMAND} -E make_directory ${generated_files_dir}
-    COMMAND ${CMAKE_COMMAND} -E echo "#define GIT_VERSION \"${version}\"" >> ${gitversion_h};
+    COMMAND ${CMAKE_COMMAND} -E echo "#define GIT_VERSION \"${version}\"" > ${gitversion_h};
     COMMENT "Generating gitversion.h"
     VERBATIM
 )