fix pdal compilation on mac (#475) (#479)

credit to Veence at https://github.com/macports/macports-ports/commit/1ed7c203f3075283309edac1a7595640d0ba9f06

vector/v.in.pdal/Makefile

@@ -6,10 +6,12 @@ LIBES = $(GPROJLIB) $(VECTORLIB) $(DBMILIB) $(GISLIB) $(MATHLIB) $(PDALLIBS)
 DEPENDENCIES = $(GPROJDEP) $(VECTORDEP) $(DBMIDEP) $(GISDEP)
 
 EXTRA_INC = $(VECT_INC) $(PROJINC) $(PDALINC)
-EXTRA_CFLAGS = $(VECT_CFLAGS) $(PDALCPPFLAGS)
+EXTRA_CFLAGS = $(VECT_CFLAGS)
 
 include $(MODULE_TOPDIR)/include/Make/Module.make
 
+$(OBJDIR)/main.o : EXTRA_CFLAGS += $(PDALCPPFLAGS)
+
 LINK = $(CXX)
 
 ifneq ($(strip $(CXX)),)