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| author | Ben Gamari <ben@smart-cactus.org> | 2021-12-23 11:53:25 -0500 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2021-12-23 12:46:05 -0500 |
| commit | ec8220b3d02c189bee4daf659446b66a594ac139 (patch) | |
| tree | 9fca0b4e54f886fd62bb416a3f4db34077d2b78c | |
| parent | ff657a81ae5ebd4ea4628ca8ebc88dce3ecbe0ef (diff) | |
| download | haskell-wip/T20861.tar.gz | |
rts: Only declare environ when necessarywip/T20861
Previously we would unconditionally provide a declaration for `environ`,
even if `<unistd.h>` already provided one. This would result in
`-Werror` builds failing on some platforms.
Also `#include <unistd.h>` to ensure that the declaration is visible.
Fixes #20861.
| -rw-r--r-- | configure.ac | 3 | ||||
| -rw-r--r-- | m4/fp_check_environ.m4 | 14 | ||||
| -rw-r--r-- | rts/RtsSymbols.c | 9 |
3 files changed, 25 insertions, 1 deletions
diff --git a/configure.ac b/configure.ac index a66c5c508a..fe1d0756e5 100644 --- a/configure.ac +++ b/configure.ac @@ -965,6 +965,9 @@ AC_CHECK_HEADERS([sys/cpuset.h], [], [], #endif ]]) +dnl ** check whether a declaration for `environ` is provided by libc. +FP_CHECK_ENVIRON + dnl ** check if it is safe to include both <time.h> and <sys/time.h> AC_HEADER_TIME diff --git a/m4/fp_check_environ.m4 b/m4/fp_check_environ.m4 new file mode 100644 index 0000000000..88bf0a52de --- /dev/null +++ b/m4/fp_check_environ.m4 @@ -0,0 +1,14 @@ +# FP_CHECK_ENVIRON +# ----------------- +AC_DEFUN([FP_CHECK_ENVIRON], +[ + dnl-------------------------------------------------------------------- + dnl * Check whether the libc headers provide a declaration for the + dnl environ symbol. If not then we will provide one in RtsSymbols.c. + dnl See #20512, #20577, #20861. + dnl-------------------------------------------------------------------- + AC_CHECK_DECLS([environ], [], [], [ + #include <unistd.h> + ]) +]) + diff --git a/rts/RtsSymbols.c b/rts/RtsSymbols.c index 7d7b8422c2..f76573e3ae 100644 --- a/rts/RtsSymbols.c +++ b/rts/RtsSymbols.c @@ -34,10 +34,17 @@ #include <elf.h> /* _DYNAMIC */ #endif +#if defined(HAVE_UNISTD_H) +#include <unistd.h> /* environ */ +#endif + +#if !HAVE_DECL_ENVIRON /* We must provide a prototype for environ since depending upon the libc - * version it may or may not be provided by unistd.h. See #20577. + * version it may or may not be provided by unistd.h. See #20577 and #20861. */ extern char **environ; +#endif + /* ----------------------------------------------------------------------------- * Symbols to be inserted into the RTS symbol table. |