diff options
Diffstat (limited to 'Configure')
| -rwxr-xr-x | Configure | 49 |
1 files changed, 49 insertions, 0 deletions
@@ -4665,6 +4665,55 @@ case "$gccversion" in esac esac +# Really old versions of gcc default to C89 and will error for this code. +# See if the compiler (gcc or otherwise) needs a flag to compile C99 code +# Initialisations in for loops seem to be the particular problem +# (Does this syntax conflict with something else that was valid C89?) +# Annoyingly -std=c99 will cause gcc to tell glibc not to define prototypes for +# syscall, drand48 etc when including <unistd.h>, which messes up our build. +# I guess we *could* loop round trying -std=c99 first with checks both for the +# prototype found and the code compiling (because -std=gnu99 might do other +# things we don't want, particularly on non-GCC compilers) but +# 1) We would need to check for the prototype first (without any flags) +# 2) We would still end up with most Linux systems either being -std=gnu99 +# or "" (no flag), and so both common options would not rigorously check our +# portability to other platforms. +# So it doesn't seem worth the complexity and chance of different failure. +$cat >try.c <<'EOCP' +int main(int argc, char **argv) { + unsigned long long count = 0; + for (char **p = argv; *p; ++p) { + ++count; + } + return count == 1 ? 0 : 1; +} +EOCP +c99_for=no +for flag in '' '-std=gnu99' '-std=c99'; do + if $cc -o try $flag $ccflags $ldflags try.c 2>/dev/null && ./try; then + c99_for="$flag" + break; + fi +done +case "$c99_for" in +'') echo "Your C compiler doesn't need any special flags to compile C99 for loops with declarations" + ;; +no) echo "Your C compiler doesn't seem to be able to compile C99 for loops with declarations" + rp='Do you really want to continue?' + dflt='n' + . ./myread + case "$ans" in + [yY]) echo >&4 "Okay, continuing." ;; + *) exit 1 ;; + esac + ;; +*) echo "Your C compiler needs $c99_for to compile C99 for loops with declarations" + ccflags="$c99_for $ccflags" + ;; +esac +$rm -f try try.* + + : What should the include directory be ? : Use sysroot if set, so findhdr looks in the right place. echo " " |