lttoolbox: Test darwin-c-level

Author: Dave-Allured

textproc/lttoolbox/Portfile

@@ -38,6 +38,13 @@ patchfiles-append       patch-ustring_h.diff
 
 compiler.cxx_standard   2017
 
+# MacOS <= 10.8.
+# https://github.com/macports/macports-ports/pull/30356#discussion_r2594470779
+if {${os.platform} eq "darwin" && ${os.major} == 10 && ${os.minor} < 9} {
+    configure.cflags-append \
+                        -D__DARWIN_C_LEVEL=__DARWIN_C_FULL
+}
+
 set python_version      313
 
 depends_build-append    path:bin/pkg-config:pkgconfig \