BUILD: compiler: undefine the CONCAT() macro if already defined

As Ilya reported in issue #2911, the CONCAT() macro breaks on NetBSD
which defines its own as __CONCAT() (which is exactly the same). Let's
just undefine it before ours to fix the issue instead of renaming, but
keep ours so that we don't have doubts about what we're running with.

Note that the patch introducing this breaking change was backported
to 3.0.

diff --git a/include/haproxy/compiler.h b/include/haproxy/compiler.h
index fc7679e8a33abbeaf393a05cd1ce5d39b2cd476f..7d42375b336d934b76ee1b3d437196bbef0b1d99 100644 (file)
--- a/include/haproxy/compiler.h
+++ b/include/haproxy/compiler.h
@@ -284,6 +284,7 @@
 #define TOSTR(x) _TOSTR(x)
 
 /* concatenates the two strings after resolving possible macros */
+#undef CONCAT // Turns out NetBSD defines it to the same in exec_elf.h
 #define _CONCAT(a,b) a ## b
 #define CONCAT(a,b) _CONCAT(a,b)