From 399d84da3708719b063953107bab0f5f6493addb Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@protonmail.com>
Date: Thu, 28 May 2020 19:06:01 +0200
Subject: [PATCH] build: Only allow ASCII identifiers

While emoji and other symbols in C++ identifers (as accepted by newer
compilers) are fun, they might create confusion during code review, for
example because some symbols look very similar. Forbid such extended
identifiers for now.

This is done by providing `-fno-extended-identifiers`. Thanks to sipa
for suggesting this compiler flag.
---
 configure.ac | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/configure.ac b/configure.ac
index 28015d005..34b8354cd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -422,6 +422,9 @@ if test "x$CXXFLAGS_overridden" = "xno"; then
   AX_CHECK_COMPILE_FLAG([-Wdeprecated-copy],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-deprecated-copy"],,[[$CXXFLAG_WERROR]])
 fi
 
+dnl Don't allow extended (non-ASCII) symbols in identifiers. This is easier for code review.
+AX_CHECK_COMPILE_FLAG([-fno-extended-identifiers],[[CXXFLAGS="$CXXFLAGS -fno-extended-identifiers"]],,[[$CXXFLAG_WERROR]])
+
 enable_sse42=no
 enable_sse41=no
 enable_avx2=no