strings-h: Don't declare strcasecmp, strncasecmp without the module.

* lib/strings.in.h (strcasecmp): Don't declare if module 'strcasecmp' is
not present.
(strncasecmp): Don't declare if module 'strncasecmp' is not present.
* m4/strings_h.m4 (gl_STRINGS_H_REQUIRE_DEFAULTS): Initialize
GNULIB_STRCASECMP, GNULIB_STRNCASECMP.
* modules/strings-h (Makefile.am): Substitute GNULIB_STRCASECMP,
GNULIB_STRNCASECMP.

ChangeLog

@@ -1,3 +1,14 @@
+2025-02-16  Bruno Haible  <bruno@clisp.org>
+
+	strings-h: Don't declare strcasecmp, strncasecmp without the module.
+	* lib/strings.in.h (strcasecmp): Don't declare if module 'strcasecmp' is
+	not present.
+	(strncasecmp): Don't declare if module 'strncasecmp' is not present.
+	* m4/strings_h.m4 (gl_STRINGS_H_REQUIRE_DEFAULTS): Initialize
+	GNULIB_STRCASECMP, GNULIB_STRNCASECMP.
+	* modules/strings-h (Makefile.am): Substitute GNULIB_STRCASECMP,
+	GNULIB_STRNCASECMP.
+
 2025-02-16  Bruno Haible  <bruno@clisp.org>
 
 	strcasecmp, strncasecmp: New modules.

lib/strings.in.h

@@ -58,8 +58,8 @@ extern "C" {
 #endif
 
 
-  /* Find the index of the least-significant set bit.  */
 #if @GNULIB_FFS@
+/* Find the index of the least-significant set bit.  */
 # if !@HAVE_FFS@
 _GL_FUNCDECL_SYS (ffs, int, (int i), );
 # endif
@@ -72,6 +72,7 @@ _GL_WARN_ON_USE (ffs, "ffs is not portable - use the ffs module");
 # endif
 #endif
 
+#if @GNULIB_STRCASECMP@
 /* Compare strings S1 and S2, ignoring case, returning less than, equal to or
    greater than zero if S1 is lexicographically less than, equal to or greater
    than S2.
@@ -80,7 +81,7 @@ _GL_WARN_ON_USE (ffs, "ffs is not portable - use the ffs module");
 extern int strcasecmp (char const *s1, char const *s2)
      _GL_ARG_NONNULL ((1, 2));
 # endif
-#if defined GNULIB_POSIXCHECK
+#elif defined GNULIB_POSIXCHECK
 /* strcasecmp() does not work with multibyte strings:
    POSIX says that it operates on "strings", and "string" in POSIX is defined
    as a sequence of bytes, not of characters.   */
@@ -95,6 +96,7 @@ _GL_WARN_ON_USE (strcasecmp, "strcasecmp cannot work correctly on character "
 # endif
 #endif
 
+#if @GNULIB_STRNCASECMP@
 /* Compare no more than N bytes of strings S1 and S2, ignoring case,
    returning less than, equal to or greater than zero if S1 is
    lexicographically less than, equal to or greater than S2.
@@ -103,7 +105,7 @@ _GL_WARN_ON_USE (strcasecmp, "strcasecmp cannot work correctly on character "
 extern int strncasecmp (char const *s1, char const *s2, size_t n)
      _GL_ARG_NONNULL ((1, 2));
 # endif
-#if defined GNULIB_POSIXCHECK
+#elif defined GNULIB_POSIXCHECK
 /* strncasecmp() does not work with multibyte strings:
    POSIX says that it operates on "strings", and "string" in POSIX is defined
    as a sequence of bytes, not of characters.  */

m4/strings_h.m4

@@ -1,5 +1,5 @@
 # strings_h.m4
-# serial 9
+# serial 10
 dnl Copyright (C) 2007, 2009-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -50,6 +50,8 @@ AC_DEFUN([gl_STRINGS_H_REQUIRE_DEFAULTS],
 [
   m4_defun(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS], [
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRCASECMP])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_STRNCASECMP])
   ])
   m4_require(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS])
   AC_REQUIRE([gl_STRINGS_H_DEFAULTS])

modules/strings-h

@@ -33,6 +33,8 @@ strings.h: strings.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(WARN_ON_USE
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_STRINGS_H''@|$(NEXT_STRINGS_H)|g' \
 	      -e 's/@''GNULIB_FFS''@/$(GNULIB_FFS)/g' \
+	      -e 's/@''GNULIB_STRCASECMP''@/$(GNULIB_STRCASECMP)/g' \
+	      -e 's/@''GNULIB_STRNCASECMP''@/$(GNULIB_STRNCASECMP)/g' \
 	      -e 's|@''HAVE_FFS''@|$(HAVE_FFS)|g' \
 	      -e 's|@''HAVE_STRCASECMP''@|$(HAVE_STRCASECMP)|g' \
 	      -e 's|@''HAVE_DECL_STRNCASECMP''@|$(HAVE_DECL_STRNCASECMP)|g' \