patch 8.2.0145: using #error for compilation errors should be OK now

Problem:    Using #error for compilation errors should be OK now.
Solution:   Use #error. (Ken Takata, closes #5299)
diff --git a/src/blowfish.c b/src/blowfish.c
index a73b3b6..af5e2fc 100644
--- a/src/blowfish.c
+++ b/src/blowfish.c
@@ -40,8 +40,7 @@
 # ifdef HAVE_CONFIG_H
    // in configure.ac AC_C_BIGENDIAN() defines WORDS_BIGENDIAN when needed
 # else
-   error!
-   Please change this code to define WORDS_BIGENDIAN for big-endian machines.
+#  error Please change this code to define WORDS_BIGENDIAN for big-endian machines.
 # endif
 #endif