PCRE_PRERELEASE is a bare sequence, not a string.

diff --git a/src/src/exim.c b/src/src/exim.c
index 670319b989db251032d98d02ae12564e4d25eff5..a6c0d7832fbc6aa7a0a8c15785e03dfec3d16dcc 100644 (file)
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -973,7 +973,9 @@ DEBUG(D_any) do {
            * unless its an ancient version of PCRE in which case it
            * is not defined */
 #ifdef PCRE_PRERELEASE
-          PCRE_PRERELEASE "",
+# define STRINGIFY(x) #x
+          STRINGIFY(PCRE_PRERELEASE) "",
+# undef STRINGIFY
 #else
           "",
 #endif