Clean up handling of missing functions.

With autotools, CMake, and nmake, if we have a function, #define
HAVE_{function_name_in_all_caps}, otherwise don't #define it.

If we provide our own version of a function in libwsutil, make sure we
have a header that declares it, and *ONLY* include that header if
HAVE_{function_name_in_all_caps} is *NOT* defined, so that we don't have
the system declaration and our declaration colliding.

Check for inet_aton, strncasecmp, and strptime with CMake, just as we do
with autotools.

Simplify the addition of {function_name_in_all_caps}_LO to libwsutil in
autotools.

Change-Id: Id5be5c73f79f81919a3a865324e400eca7b88889
Reviewed-on: https://code.wireshark.org/review/2903
Reviewed-by: Guy Harris <guy@alum.mit.edu>

4 files changed, 47 insertions, 26 deletions

diff --git a/wsutil/Makefile.am b/wsutil/Makefile.am
index 385acc6e73..c2e0c22186 100644
--- a/wsutil/Makefile.am
+++ b/wsutil/Makefile.am
@@ -25,32 +25,14 @@ DIST_SUBDIRS = $(SUBDIRS)
 ACLOCAL_AMFLAGS = `../aclocal-flags`
 
 # Optional objects that I know how to build. These will be
-# linked into libwsutil.
-wsutil_optional_objects =
-
-if NEED_GETOPT_LO
-wsutil_optional_objects += @GETOPT_LO@
-endif
-
-if NEED_INET_ATON_LO
-wsutil_optional_objects += @INET_ATON_LO@
-endif
-
-if NEED_INET_NTOP_LO
-wsutil_optional_objects += @INET_NTOP_LO@
-endif
-
-if NEED_INET_PTON_LO
-wsutil_optional_objects += @INET_PTON_LO@
-endif
-
-if NEED_STRNCASECMP_LO
-wsutil_optional_objects += @STRNCASECMP_LO@
-endif
-
-if NEED_STRPTIME_LO
-wsutil_optional_objects += @STRPTIME_LO@
-endif
+# linked into libwsutil if necessary.
+wsutil_optional_objects = \
+	@GETOPT_LO@		\
+	@INET_ATON_LO@		\
+	@INET_NTOP_LO@		\
+	@INET_PTON_LO@		\
+	@STRNCASECMP_LO@	\
+	@STRPTIME_LO@
 
 if SSE42_SUPPORTED
 wsutil_optional_objects += libwsutil_sse42.la
@@ -92,6 +74,7 @@ EXTRA_libwsutil_la_SOURCES=	\
 	inet_pton.c		\
 	inet_v6defs.h		\
 	strncasecmp.c		\
+	strncasecmp.h		\
 	strptime.c		\
 	strptime.h		\
 	wsgetopt.c		\
diff --git a/wsutil/strncasecmp.c b/wsutil/strncasecmp.c
index da8b862482..57953b9f04 100644
--- a/wsutil/strncasecmp.c
+++ b/wsutil/strncasecmp.c
@@ -21,6 +21,8 @@
 #include <string.h>
 #include <ctype.h>
 
+#include "wsutil/strncasecmp.h"
+
 /* Compare no more than N characters of S1 and S2,
    ignoring case, returning less than, equal to or
    greater than zero if S1 is lexicographically less
diff --git a/wsutil/strncasecmp.h b/wsutil/strncasecmp.h
new file mode 100644
index 0000000000..bfc3b63561
--- /dev/null
+++ b/wsutil/strncasecmp.h
@@ -0,0 +1,32 @@
+/* strncasecmp.h
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __STRNCASECMP_H__
+#define __STRNCASECMP_H__
+
+#include "ws_symbol_export.h"
+
+/*
+ * Version of "strncasecmp()", for the benefit of OSes that don't have it.
+ */
+WS_DLL_PUBLIC int strncasecmp (const char *, const char *, size_t);
+
+#endif
diff --git a/wsutil/strptime.c b/wsutil/strptime.c
index d6603a9d53..7a8fe2a13e 100644
--- a/wsutil/strptime.c
+++ b/wsutil/strptime.c
@@ -31,6 +31,10 @@
 #include <string.h>
 #include <time.h>
 
+#ifndef HAVE_STRNCASECMP
+#include "wsutil/strncasecmp.h"
+#endif
+
 #ifdef _LIBC
 # include "../locale/localeinfo.h"
 #endif