Re: Interference between two installations of gnulib

[Bruno Haible]

These patches caused a build failure in GNU libunistring:

gcc -DHAVE_CONFIG_H -DEXEEXT=\"\" -I. -I../../../sources/libunistring/tests 
-I../lib -I..  -DIN_LIBUNISTRING_GNULIB_TESTS=1 -I. 
-I../../../sources/libunistring/tests -I.. 
-I../../../sources/libunistring/tests/.. -I../lib 
-I../../../sources/libunistring/tests/../lib -Wall  -g -O2 -MT locale.o -MD -MP 
-MF $depbase.Tpo -c -o locale.o ../../../sources/libunistring/tests/locale.c &&\
mv -f $depbase.Tpo $depbase.Po
In file included from ../../../sources/libunistring/tests/locale.c:22:0:
./stdio.h:830:5: error: #if with no expression
./stdio.h:846:5: error: #if with no expression
...

The problem is that the macro gl_STDIO_H_REQUIRE_DEFAULTS must only be invoked,
never AC_REQUIREd. Hence all gl_STDIO_MODULE_INDICATOR invocations must also
only be invoked, never AC_REQUIREd. But gl_STDIO_H is automatically AC_REQUIREd,
since it is defined through AC_DEFUN_ONCE.

This patch fixes it.


2021-04-17  Bruno Haible  <bruno@clisp.org>

        stdio: Fix build error in some configurations (regression 2021-04-11).
        * m4/stdio_h.m4 (gl_STDIO_H): Move gl_STDIO_MODULE_INDICATOR and
        gl_MODULE_INDICATOR invocations from here...
        * modules/stdio (configure.ac): ... to here.

diff --git a/m4/stdio_h.m4 b/m4/stdio_h.m4
index 6846ca6..d9820e4 100644
--- a/m4/stdio_h.m4
+++ b/m4/stdio_h.m4
@@ -1,4 +1,4 @@
-# stdio_h.m4 serial 54
+# stdio_h.m4 serial 55
 dnl Copyright (C) 2007-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -40,17 +40,6 @@ AC_DEFUN_ONCE([gl_STDIO_H],
        attribute "__gnu_printf__" instead of "__printf__"])
   fi
 
-  dnl No need to create extra modules for these functions. Everyone who uses
-  dnl <stdio.h> likely needs them.
-  gl_STDIO_MODULE_INDICATOR([fscanf])
-  gl_MODULE_INDICATOR([fscanf])
-  gl_STDIO_MODULE_INDICATOR([scanf])
-  gl_MODULE_INDICATOR([scanf])
-  gl_STDIO_MODULE_INDICATOR([fgetc])
-  gl_STDIO_MODULE_INDICATOR([getc])
-  gl_STDIO_MODULE_INDICATOR([getchar])
-  gl_STDIO_MODULE_INDICATOR([fgets])
-  gl_STDIO_MODULE_INDICATOR([fread])
   dnl This ifdef is necessary to avoid an error "missing file lib/stdio-read.c"
   dnl "expected source file, required through AC_LIBSOURCES, not found". It is
   dnl also an optimization, to avoid performing a configure check whose result
@@ -64,18 +53,6 @@ AC_DEFUN_ONCE([gl_STDIO_H],
     fi
   ])
 
-  dnl No need to create extra modules for these functions. Everyone who uses
-  dnl <stdio.h> likely needs them.
-  gl_STDIO_MODULE_INDICATOR([fprintf])
-  gl_STDIO_MODULE_INDICATOR([printf])
-  gl_STDIO_MODULE_INDICATOR([vfprintf])
-  gl_STDIO_MODULE_INDICATOR([vprintf])
-  gl_STDIO_MODULE_INDICATOR([fputc])
-  gl_STDIO_MODULE_INDICATOR([putc])
-  gl_STDIO_MODULE_INDICATOR([putchar])
-  gl_STDIO_MODULE_INDICATOR([fputs])
-  gl_STDIO_MODULE_INDICATOR([puts])
-  gl_STDIO_MODULE_INDICATOR([fwrite])
   dnl This ifdef is necessary to avoid an error "missing file 
lib/stdio-write.c"
   dnl "expected source file, required through AC_LIBSOURCES, not found". It is
   dnl also an optimization, to avoid performing a configure check whose result
diff --git a/modules/stdio b/modules/stdio
index 18c24d7..e13b689 100644
--- a/modules/stdio
+++ b/modules/stdio
@@ -19,6 +19,31 @@ configure.ac:
 gl_STDIO_H
 gl_STDIO_H_REQUIRE_DEFAULTS
 
+dnl No need to create extra modules for these functions. Everyone who uses
+dnl <stdio.h> likely needs them.
+gl_STDIO_MODULE_INDICATOR([fscanf])
+gl_MODULE_INDICATOR([fscanf])
+gl_STDIO_MODULE_INDICATOR([scanf])
+gl_MODULE_INDICATOR([scanf])
+gl_STDIO_MODULE_INDICATOR([fgetc])
+gl_STDIO_MODULE_INDICATOR([getc])
+gl_STDIO_MODULE_INDICATOR([getchar])
+gl_STDIO_MODULE_INDICATOR([fgets])
+gl_STDIO_MODULE_INDICATOR([fread])
+
+dnl No need to create extra modules for these functions. Everyone who uses
+dnl <stdio.h> likely needs them.
+gl_STDIO_MODULE_INDICATOR([fprintf])
+gl_STDIO_MODULE_INDICATOR([printf])
+gl_STDIO_MODULE_INDICATOR([vfprintf])
+gl_STDIO_MODULE_INDICATOR([vprintf])
+gl_STDIO_MODULE_INDICATOR([fputc])
+gl_STDIO_MODULE_INDICATOR([putc])
+gl_STDIO_MODULE_INDICATOR([putchar])
+gl_STDIO_MODULE_INDICATOR([fputs])
+gl_STDIO_MODULE_INDICATOR([puts])
+gl_STDIO_MODULE_INDICATOR([fwrite])
+
 Makefile.am:
 BUILT_SOURCES += stdio.h