kbuild: error out early in make headers_install

Fix the a.out.h case by setting SRCARCH and error
out early in case of an error.
The a.out.h case failed with the *_all targets.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/Makefile b/Makefile
index f950661..33e735c 100644
--- a/Makefile
+++ b/Makefile
@@ -1026,8 +1026,9 @@
 
 PHONY += headers_install_all
 headers_install_all: __headers
-	$(Q)for arch in $(hdr-archs); do \
-	 $(MAKE) ARCH=$$arch $(hdr-inst)=include BIASMDIR=-bi-$$arch ;\
+	$(Q)set -e; for arch in $(hdr-archs); do \
+	 $(MAKE) ARCH=$$arch SRCARCH=$$arch $(hdr-inst)=include \
+	         BIASMDIR=-bi-$$arch ;\
 	 done
 
 PHONY += headers_install
@@ -1040,8 +1041,9 @@
 
 PHONY += headers_check_all
 headers_check_all: headers_install_all
-	$(Q)for arch in $(hdr-archs); do \
-	 $(MAKE) ARCH=$$arch $(hdr-inst)=include BIASMDIR=-bi-$$arch HDRCHECK=1 ;\
+	$(Q)set -e; for arch in $(hdr-archs); do \
+	 $(MAKE) ARCH=$$arch SRCARCH=$$arch $(hdr-inst)=include \
+	         BIASMDIR=-bi-$$arch HDRCHECK=1 ;\
 	 done
 
 PHONY += headers_check