make: pass GDAL include dirs to libgproj (#6631)

vector_inc and vedit_inc don't need this treatment as VECT_CFLAGS has it
added already. This would conform to how its done in the CMakeLists.txt
as well.

Oddly enough this isn't a fatal error though. So if anyone hit a build
failure and thought this was the issue should look further into their
builds logs for the actual cause.

Bug: #4258

Signed-off-by: Alfred Wingate <[email protected]>

Author: parona-source

python/libgrass_interface_generator/Makefile

@@ -52,7 +52,7 @@ segment_HDRS    = segment.h defs/segment.h
 rowio_HDRS      = rowio.h defs/rowio.h
 temporal_HDRS   = temporal.h
 
-proj_INC        = $(PROJINC)
+proj_INC        = $(PROJINC) $(GDALCFLAGS)
 vector_INC      = $(VECT_INC) $(VECT_CFLAGS)
 vedit_INC       = $(VECT_INC) $(VECT_CFLAGS)