pack: CMake: set also _BLD_gvc

This is a temporary measure until an upcoming commit series cleans up
the control of the Windows storage-class attributes.

Without this change, an upcoming commit that defines GVDLL also for
CMake builds, would cause many errors like this with minGW:

pack/CMakeFiles/pack_obj.dir/ccomps.c.obj:ccomps.c:(.text+0x1c95): undefined reference to `__imp_Verbose'

diff --git a/lib/pack/CMakeLists.txt b/lib/pack/CMakeLists.txt
index 384d231d7c4ee80fed255ae9a7a4627a280d0f15..ba3d9419e843416a8e7b6588212b89f9ebc43100 100644 (file)
--- a/lib/pack/CMakeLists.txt
+++ b/lib/pack/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_definitions(-DGVC_EXPORTS)
+add_definitions(-D_BLD_gvc -DGVC_EXPORTS)
 
 add_library(pack_obj OBJECT
     # Header files