[binutils-gdb/gdb-17-branch] gdb/ser-unix: work around conflicting types for tcflag_t

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2636da31af44fab38c22cee0fe771761173ea64b

commit 2636da31af44fab38c22cee0fe771761173ea64b
Author: Simon Marchi <[email protected]>
Date:   Mon Nov 17 16:25:18 2025 -0500

    gdb/ser-unix: work around conflicting types for tcflag_t
    
    When trying to cross-compile GDB to sparc-buildroot-linux-uclibc, I get:
    
          CXX    ser-unix.o
        In file included from /data1/smarchi/many-buildroots/toolchains/sparc/sparc-buildroot-linux-uclibc/sysroot/usr/include/termios.h:39,
                         from /home/smarchi/src/binutils-gdb/gdb/ser-unix.c:51:
        /data1/smarchi/many-buildroots/toolchains/sparc/sparc-buildroot-linux-uclibc/sysroot/usr/include/bits/termios.h:26:22: error: conflicting declaration ‘typedef unsigned int tcflag_t’
           26 | typedef unsigned int tcflag_t;
              |                      ^~~~~~~~
        In file included from /home/smarchi/src/binutils-gdb/gdb/ser-unix.c:46:
        /data1/smarchi/many-buildroots/toolchains/sparc/sparc-buildroot-linux-uclibc/sysroot/usr/include/asm/termbits.h:13:25: note: previous declaration as ‘typedef long unsigned int tcflag_t’
           13 | typedef unsigned long   tcflag_t;
              |                         ^~~~~~~~
    
    uClibc and the kernel don't agree on the definition of tcflag_t for this
    architecture.  Here' uClibc [1]:
    
        typedef unsigned int tcflag_t;
    
    And here's the kernel [2]:
    
        #if defined(__sparc__) && defined(__arch64__)
        typedef unsigned int        tcflag_t;
        #else
        typedef unsigned long       tcflag_t; <--- that branch is take
        #endif
    
    glibc [3] has the same definition as uClibc, so we would get the same
    problem.
    
    I propose to work around this the same way as we handle differences in
    the termios structure, by renaming the version from the kernel.
    
    I opened a bug on the glibc bugzilla [4] to ask if this is something
    that would need to be fixed on the libc side, but in the mean time we
    need to work around it.
    
    [1] https://github.com/kraj/uClibc/blob/ca1c74d67dd115d059a875150e10b8560a9c35a8/libc/sysdeps/linux/sparc/bits/termios.h#L26
    [2] https://github.com/torvalds/linux/blob/e7c375b181600caf135cfd03eadbc45eb530f2cb/arch/sparc/include/uapi/asm/termbits.h#L7-L11
    [3] https://gitlab.com/gnutools/glibc/-/blob/efc8642051e6c4fe5165e8986c1338ba2c180de6/bits/termios.h#L104
    [4] https://sourceware.org/bugzilla/show_bug.cgi?id=33643
    
    Change-Id: I71c6e0df5ac8e2ff3db3233a2220faaf70c3df6d
    Approved-By: Tom Tromey <[email protected]>
    (cherry picked from commit 6b84377e146794446f21371f8455b870a029cc8e)

Diff:
---
 gdb/ser-unix.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gdb/ser-unix.c b/gdb/ser-unix.c
index 5ec664df1f3..50c0fdddf6d 100644
--- a/gdb/ser-unix.c
+++ b/gdb/ser-unix.c
@@ -43,8 +43,10 @@
 /* Workaround to resolve conflicting declarations of termios
    in <asm/termbits.h> and <termios.h>.  */
 #  define termios asmtermios
+#  define tcflag_t asmtcflag_t
 #  include <asm/termbits.h>
 #  undef termios
+#  undef tcflag_t
 #endif
 
 #ifdef HAVE_TERMIOS_H