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authorLibravatar Ronald Wampler <rdwampler@gmail.com>2016-07-07 16:45:54 -0400
committerLibravatar Junio C Hamano <gitster@pobox.com>2016-07-07 14:15:08 -0700
commitd19e3a5b21f28c07886801616e02e08eab64a7d8 (patch)
treef3ad8e4dbce119ebe2a4bbde60b041a44177f0b6 /Makefile
parentGit 2.8.4 (diff)
downloadtgif-d19e3a5b21f28c07886801616e02e08eab64a7d8.tar.xz
Makefile: add NEEDS_LIBRT to optionally link with librt
We unconditionally link with librt, when HAVE_CLOCK_GETTIME is defined. But clock_gettime() has been available in most libc implementations for some time now (e.g., for glibc since version 2.17) and no longer requires linking with librt. Furthermore, commit a6c3c63 (configure.ac: check for clock_gettime() and CLOCK_MONOTONIC) will automatically determined which library (libc or librt) is required for linking when checking for clock_gettime(). The assumption to unconditionally link with librt was OK, since either almost every Unix-like system provides a version of librt for backwards compatibility or other systems, namely Windows or OS X, never provided clock_gettime(). However, in the latest release of OS X (macOS Sierra), this function has been added to OS X libc version. As a result, when running the configuration script, HAVE_CLOCK_GETTIME is set and since librt is not present, it causes a linker error. This patches requires those not building via the configuration scripts to define NEEDS_LIBRT in addition to HAVE_CLOCK_GETTIME, if needed. Signed-off-by: Ronald Wampler <rdwampler@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile12
1 files changed, 9 insertions, 3 deletions
diff --git a/Makefile b/Makefile
index e11e626d05..949925e946 100644
--- a/Makefile
+++ b/Makefile
@@ -351,9 +351,12 @@ all::
# Define GMTIME_UNRELIABLE_ERRORS if your gmtime() function does not
# return NULL when it receives a bogus time_t.
#
-# Define HAVE_CLOCK_GETTIME if your platform has clock_gettime in librt.
+# Define HAVE_CLOCK_GETTIME if your platform has clock_gettime.
#
-# Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC in librt.
+# Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC.
+#
+# Define NEEDS_LIBRT if your platform requires linking with librt (glibc version
+# before 2.17) for clock_gettime and CLOCK_MONOTONIC.
#
# Define USE_PARENS_AROUND_GETTEXT_N to "yes" if your compiler happily
# compiles the following initialization:
@@ -1465,13 +1468,16 @@ endif
ifdef HAVE_CLOCK_GETTIME
BASIC_CFLAGS += -DHAVE_CLOCK_GETTIME
- EXTLIBS += -lrt
endif
ifdef HAVE_CLOCK_MONOTONIC
BASIC_CFLAGS += -DHAVE_CLOCK_MONOTONIC
endif
+ifdef NEEDS_LIBRT
+ EXTLIBS += -lrt
+endif
+
ifdef HAVE_BSD_SYSCTL
BASIC_CFLAGS += -DHAVE_BSD_SYSCTL
endif