extconf.rb: apply RUBY_OPENSSL_EXT{C,LD}FLAGS after checking features

RUBY_OPENSSL_EXTCFLAGS and RUBY_OPENSSL_EXTLDFLAGS have been added for
the primary purpose of appending custom warning flags during
development and CI.

Since checking programs generated by mkmf may not be completely
warning-free, we don't want to apply -Werror that may be supplied from
those environment variables.

Author: rhenium

ext/openssl/extconf.rb

@@ -18,12 +18,6 @@
 
 Logging::message "=== OpenSSL for Ruby configurator ===\n"
 
-# Append flags from environment variables.
-extcflags = ENV["RUBY_OPENSSL_EXTCFLAGS"]
-append_cflags(extcflags.split) if extcflags
-extldflags = ENV["RUBY_OPENSSL_EXTLDFLAGS"]
-append_ldflags(extldflags.split) if extldflags
-
 ##
 # Adds -DOSSL_DEBUG for compilation and some more targets when GCC is used
 # To turn it on, use: --with-debug or --enable-debug
@@ -198,6 +192,12 @@ def find_openssl_library
 
 Logging::message "=== Checking done. ===\n"
 
+# Append flags from environment variables.
+extcflags = ENV["RUBY_OPENSSL_EXTCFLAGS"]
+append_cflags(extcflags.split) if extcflags
+extldflags = ENV["RUBY_OPENSSL_EXTLDFLAGS"]
+append_ldflags(extldflags.split) if extldflags
+
 create_header
 create_makefile("openssl")
 Logging::message "Done.\n"