[scons] workaround FreeBSD11 fullstatic link error

The error for reference:

/usr/lib/libc.a(arc4random.o): In function `arc4random':
/usr/src/lib/libc/gen/arc4random.c:(.text+0x410): multiple definition of `arc4random'
/usr/local/lib/libcrypto.a(arc4random.o):(.text+0x0): first defined here
/usr/lib/libc.a(arc4random.o): In function `arc4random_buf':
/usr/src/lib/libc/gen/arc4random.c:(.text+0x580): multiple definition of `arc4random_buf'
/usr/local/lib/libcrypto.a(arc4random.o):(.text+0x80): first defined here

src/SConscript

@@ -35,8 +35,18 @@ def RemoveDuplicateLibs(libs):
 
 Import('env')
 
+def WorkaroundFreeBSDLibOrder(libs):
+	# lib(re)ssl includes (weak) arc4random functions
+	# which "on purpose" might conflict with those in libc
+	# => link libc first solves this
+	# (required for FreeBSD11 fullstatic build)
+	if 'c' in libs:
+		return ['c'] + libs
+	return libs
+
 def GatherLibs(env, *libs):
-	return RemoveDuplicateLibs(env['LIBS'] + list(libs) + [env['APPEND_LIBS']])
+	libs = RemoveDuplicateLibs(env['LIBS'] + list(libs) + [env['APPEND_LIBS']])
+	return WorkaroundFreeBSDLibOrder(libs)
 
 common_src = Split("base64.c buffer.c log.c \
 	keyvalue.c chunk.c  \