Add configure and build support for the pthreads library

Support for pthreads can be forcibly disabled by passing
"--without-pthread" to the configure script.

The actual changes in this commit are in configure.ac and MCONFIG.in;
the other files were generated as a result of running aclocal,
autoconf, and autoheader on a Debian testing system.

Note: the autoconf-archive package must now be installed before
rerunning aclocal, to supply the AX_PTHREAD macro.

Signed-off-by: Theodore Ts'o <[email protected]>

MCONFIG.in

@@ -86,15 +86,17 @@ SYSTEMD_SYSTEM_UNIT_DIR = @systemd_system_unit_dir@
 SANITIZER_CFLAGS = @lto_cflags@ @ubsan_cflags@ @addrsan_cflags@ @threadsan_cflags@
 SANITIZER_LDFLAGS = @lto_ldflags@ @ubsan_ldflags@ @addrsan_ldflags@ @threadsan_ldflags@
 
-CC = @CC@
+CC = @PTHREAD_CC@
 BUILD_CC = @BUILD_CC@
+PTHREAD_CFLAGS = @PTHREAD_CFLAGS@
+PTHREAD_LIBS = @PTHREAD_LIBS@
 CFLAGS = @CFLAGS@
 CFLAGS_SHLIB = @CFLAGS_SHLIB@
 CFLAGS_STLIB = @CFLAGS_STLIB@
 CPPFLAGS = @INCLUDES@
-ALL_CFLAGS = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
-ALL_CFLAGS_SHLIB = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS_SHLIB) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
-ALL_CFLAGS_STLIB = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS_STLIB) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
+ALL_CFLAGS = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS) $(PTHREAD_CFLAGS) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
+ALL_CFLAGS_SHLIB = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS_SHLIB) $(PTHREAD_CFLAGS) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
+ALL_CFLAGS_STLIB = $(CPPFLAGS) $(SANITIZER_CFLAGS) $(CFLAGS_STLIB) $(PTHREAD_CFLAGS) $(CFLAGS_WARN) @DEFS@ $(LOCAL_CFLAGS)
 LDFLAGS = $(SANITIZER_LDFLAGS) @LDFLAGS@
 LDFLAGS_SHLIB = $(SANITIZER_LDFLAGS) @LDFLAGS_SHLIB@
 ALL_LDFLAGS = $(LDFLAGS) @LDFLAG_DYNAMIC@
@@ -138,7 +140,7 @@ LIBFUSE = @FUSE_LIB@
 LIBSUPPORT = $(LIBINTL) $(LIB)/libsupport@STATIC_LIB_EXT@
 LIBBLKID = @LIBBLKID@ @PRIVATE_LIBS_CMT@ $(LIBUUID)
 LIBINTL = @LIBINTL@
-SYSLIBS = @LIBS@
+SYSLIBS = @LIBS@ @PTHREAD_LIBS@
 DEPLIBSS = $(LIB)/libss@LIB_EXT@
 DEPLIBCOM_ERR = $(LIB)/libcom_err@LIB_EXT@
 DEPLIBUUID = @DEPLIBUUID@