ta: also build GP TAs when GP_PACKAGE is set

Add the GlobalPlatform Test Suite TAs to the build when GP_PACKAGE is
set. This happens in the OP-TEE build environment [1], which still handles
the package extraction step as well as the final installation of the TAs
into the staging directory.

Link: https://github.com/OP-TEE/build/blob/4.2.0/br-ext/package/optee_test_ext/optee_test_ext.mk [1]
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>

ta/Makefile.gmake

@@ -62,6 +62,20 @@ $(eval $(foreach dir,$(TA_DIRS),$(call add-ta-target,$(dir))))
 
 ta-os_test: ta-os_test_lib ta-os_test_lib_dl
 
+ifneq (,$(GP_PACKAGE))
+define add-gp-ta-target
+.PHONY: gp-ta-$(1)
+gp-ta-$(1):
+	$(MAKE) -C $(1)
+
+ta: gp-ta-$(1)
+
+endef
+
+$(eval $(foreach f,$(dir $(wildcard ../host/xtest/gp-suite/TTAs_Internal_API_1_1_1/*/*/code_files/Makefile \
+	../host/xtest/gp-suite/TTAs_Internal_API_1_1_1/*/*/*/code_files/Makefile)),$(call add-gp-ta-target,$(f))))
+endif
+
 # remove build directories including ta/<ta-name>/ directories.
 # Note: $(out-dir) may be a relative path.
 RMDIR := rmdir --ignore-fail-on-non-empty