Generalize the inclusion of strings.h

The header strings.h was formerly only included for HP NonStop (aka
Tandem) to define strcasecmp, but another platform requiring this
inclusion has been found.  The build system will now include the
file based on its presence determined by configure.

Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -74,6 +74,8 @@ all::
 # Define NO_D_TYPE_IN_DIRENT if your platform defines DT_UNKNOWN but lacks
 # d_type in struct dirent (Cygwin 1.5, fixed in Cygwin 1.7).
 #
+# Define HAVE_STRINGS_H if you have strings.h and need it for strcasecmp.
+#
 # Define NO_STRCASESTR if you don't have strcasestr.
 #
 # Define NO_MEMMEM if you don't have memmem.
@@ -1350,6 +1352,7 @@ ifeq ($(uname_S),NONSTOP_KERNEL)
 	# Added manually, see above.
 	NEEDS_SSL_WITH_CURL = YesPlease
 	HAVE_LIBCHARSET_H = YesPlease
+	HAVE_STRINGS_H = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	NEEDS_LIBINTL_BEFORE_LIBICONV = YesPlease
 	NO_SYS_SELECT_H = UnfortunatelyYes
@@ -1883,6 +1886,10 @@ ifdef HAVE_LIBCHARSET_H
 	EXTLIBS += $(CHARSET_LIB)
 endif
 
+ifdef HAVE_STRINGS_H
+	BASIC_CFLAGS += -DHAVE_STRINGS_H
+endif
+
 ifdef HAVE_DEV_TTY
 	BASIC_CFLAGS += -DHAVE_DEV_TTY
 endif

configure.ac

@@ -886,6 +886,12 @@ AC_CHECK_HEADER([libcharset.h],
 [HAVE_LIBCHARSET_H=YesPlease],
 [HAVE_LIBCHARSET_H=])
 GIT_CONF_SUBST([HAVE_LIBCHARSET_H])
+#
+# Define HAVE_STRINGS_H if you have strings.h
+AC_CHECK_HEADER([strings.h],
+[HAVE_STRINGS_H=YesPlease],
+[HAVE_STRINGS_H=])
+GIT_CONF_SUBST([HAVE_STRINGS_H])
 # Define CHARSET_LIB if libiconv does not export the locale_charset symbol
 # and libcharset does
 CHARSET_LIB=

git-compat-util.h

@@ -99,7 +99,7 @@
 #include <stdlib.h>
 #include <stdarg.h>
 #include <string.h>
-#ifdef __TANDEM /* or HAVE_STRINGS_H or !NO_STRINGS_H? */
+#ifdef HAVE_STRINGS_H
 #include <strings.h> /* for strcasecmp() */
 #endif
 #include <errno.h>