Add export for GPR_PROJECT_PATH.

It has been reported that on Rocky OS without the export the
GPR_PROJECT_PATH variable is not properly passed to child
process.

Fixes eng/toolchain/aws#36.

Author: TurboGit

Makefile

@@ -59,7 +59,7 @@ OOTDIR := /$(TARGET)
 endif
 
 # Add path to generated project files
-GPR_PROJECT_PATH := $(PRJ_DIR)$(PSEP)$(GPR_PROJECT_PATH)
+export GPR_PROJECT_PATH := $(PRJ_DIR)$(PSEP)$(GPR_PROJECT_PATH)
 
 LIBAWS_TYPES := static