Fix FreeBSD build.

- Recent changes to the build system appear to make the assumption
  that the GNU regex APIs are universally available. This isn't the
  case on FreeBSD, which requires libgnuregex to provide that
  functionality. This broke the host keymap build.

build/jam/BuildSetup

@@ -573,7 +573,7 @@ HOST_HDRS += [ FDirName $(HAIKU_TOP) headers build host $(HOST_PLATFORM) ] ;
 if $(HOST_PLATFORM) = freebsd {
 	# FreeBSD's gcc doesn't include /usr/local/* in its search paths,
 	# though that's where most things from ports wind up being installed.
-	HOST_HDRS += /usr/local/include ;
+	HOST_HDRS += /usr/local/include /usr/include/gnu ;
 	HOST_LINKFLAGS += -L/usr/local/lib ;
 }
 

src/tools/keymap/Jamfile

@@ -7,6 +7,7 @@ SEARCH_SOURCE += [ FDirName $(HAIKU_TOP) src bin keymap ] ;
 USES_BE_API on <build>keymap = true ;
 
 local regexSources ;
+local regexLib ;
 
 if $(HOST_PLATFORM) = cygwin || $(HOST_PLATFORM) = sunos {
 	UseHeaders [ FDirName $(HAIKU_TOP) src system libroot posix glibc regex ] ;
@@ -14,11 +15,16 @@ if $(HOST_PLATFORM) = cygwin || $(HOST_PLATFORM) = sunos {
 	regexSources = regex.c ;
 }
 
+# FreeBSD isolates the GNU-style functions and structures into their own library.
+if $(HOST_PLATFORM) = freebsd {
+	regexLib = gnuregex ;
+}
+
 BuildPlatformMain <build>keymap :
 	main.cpp
 	Keymap.cpp
 	$(regexSources)
-	: libshared_build.a $(HOST_LIBSTDC++) $(HOST_LIBSUPC++)
+	: libshared_build.a $(HOST_LIBSTDC++) $(HOST_LIBSUPC++) $(regexLib)
 ;
 
 LinkAgainst <build>keymap : $(HOST_LIBBE) ;