--- a/make/autoconf/spec.gmk.in	Wed Oct 09 14:07:44 2019 +0200
+++ b/make/autoconf/spec.gmk.in	Fri Oct 11 09:43:18 2019 +0200
@@ -51,6 +51,9 @@
 # What make to use for main processing, after bootstrapping top-level Makefile.
 MAKE := @MAKE@
 
+# Make sure all shell commands are executed with the C locale
+export LC_ALL := C
+
 # The default make arguments
 MAKE_ARGS = $(MAKE_LOG_FLAGS) -r -R -I $(TOPDIR)/make/common SPEC=$(SPEC) \
     MAKE_LOG_FLAGS="$(MAKE_LOG_FLAGS)" $(MAKE_LOG_VARS)