do not globally export gb_AWK, GBUILDDIR, SRCDIR, gb_XSLTPROC

solenv/gbuild/CustomTarget.mk

@@ -30,6 +30,7 @@
 define gb_CustomTarget__command
 +$(call gb_Helper_abbreviate_dirs,\
 	mkdir -p $(call gb_CustomTarget_get_workdir,$(2)) && \
+	gb_AWK=$(gb_AWK) gb_XSLTPROC=$(gb_XSLTPROC) GBUILDDIR=$(GBUILDDIR) SRCDIR=$(SRCDIR) \
 	$(MAKE) -C $(call gb_CustomTarget_get_workdir,$(2)) -f $< && \
 	touch $(1))
 

solenv/gbuild/gbuild.mk

@@ -331,12 +331,6 @@ gb_PYTHONTARGET := $(OUTDIR)/bin/python
 gb_PYTHON := $(gb_PYTHON_PRECOMMAND) $(gb_PYTHONTARGET)
 endif
 
-export gb_AWK
-export gb_XSLTPROC
-export GBUILDDIR
-# FIXME exporting SRCDIR seems kind of a hack
-export SRCDIR
-
 define gb_HelpMessage
 NAME
        gbuild - GNU make based build system for LibreOffice