The build_data.c is dynamically generated by configure, sometimes the data may not be synchronized to the file build_data.c, as a result, it will break the compilation process with the following error: $ for i in {1..50} ; do make clean ; rm -rf gdb-10.2/ ; make warn ;\ [ $? -ne 0 ] && echo "TRY $i" && break ; done ... ar: creating crashlib.a CXXLD gdb /usr/bin/ld: ../../crashlib.a(main.o): in function `dump_build_data': /home/crash/main.c:1829: undefined reference to `build_command' /usr/bin/ld: /home/crash/main.c:1830: undefined reference to `build_data' collect2: error: ld returned 1 exit status make[4]: *** [Makefile:1872: gdb] Error 1 make[3]: *** [Makefile:10072: all-gdb] Error 2 make[2]: *** [Makefile:860: all] Error 2 crash build failed The fflush() will help flush the data into the build_data.c. Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; --- configure.c | 1 + 1 file changed, 1 insertion(+) diff --git a/configure.c b/configure.c index 51888519c18c..41d096bc56ca 100644 --- a/configure.c +++ b/configure.c @@ -1337,6 +1337,7 @@ make_build_data(char *target) pclose(fp1); pclose(fp2); pclose(fp3); + fflush(fp4); fclose(fp4); } -- 2.20.1