changed configure.ac not to add pthread options to cflags by default

qse/configure

@@ -1495,7 +1495,7 @@ Optional Features:
   --enable-debug          build the library in the debug mode (default. no)
   --enable-cxx            build the library for C++ if a C++ compiler is
                           available (default. yes)
-  --enable-reentrant      define _REENTRANT (default. yes)
+  --enable-reentrant      add thread options (default. no)
   --enable-sedtracer      enable qse_sed_setexectracer() (default. yes)
 
 Optional Packages:
@@ -20408,15 +20408,6 @@ else
 fi
 
 
-# Check whether --enable-reentrant was given.
-if test "${enable_reentrant+set}" = set; then :
-  enableval=$enable_reentrant; enable_reentrant_is=$enableval
-else
-  enable_reentrant_is=yes
-fi
-
-if test "$enable_reentrant_is" = "yes"
-then
 
 
 ac_ext=c
@@ -20813,6 +20804,15 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
+# Check whether --enable-reentrant was given.
+if test "${enable_reentrant+set}" = set; then :
+  enableval=$enable_reentrant; enable_reentrant_is=$enableval
+else
+  enable_reentrant_is=no
+fi
+
+if test "$enable_reentrant_is" = "yes"
+then
 	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
 	CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS"
 fi