[PATCH 1/1] Makefile.build: Add an explicit error for missing ASN.1 compiler

[James Bottomley <James.Bottomley@HansenPartnership.com>]

The current dependency rules mean that the build breaks if the ASN.1
compiler is required but CONFIG_ASN1 isn't set.  However, it isn't
obvious from the error message about missing files what the actual
problem is, so make the build system give an explicit error.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---
 scripts/Makefile.build | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a467b9323442..bca7003beac8 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -382,6 +382,11 @@ quiet_cmd_asn1_compiler = ASN.1   $(basename $@).[ch]
       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
 				$(basename $@).c $(basename $@).h
 
+ifndef CONFIG_ASN1
+$(objtree)/scripts/asn1_compiler:
+	$(error CONFIG_ASN1 must be defined for the asn1_compiler)
+endif
+
 $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 	$(call cmd,asn1_compiler)
 
-- 
2.26.2