Clean up C pre-processor mess

Currently, large parts of the C source use pre-processor tricks for
maintaining compatibility between versions 5 and 7 of PHP. This contains
work for cleaning the dependencies up by introducing an extra level of C
source, tailored to each supported version of PHP.

engine/engine.c

@@ -26,11 +26,7 @@ const char engine_ini_defaults[] = {
 	"max_input_time = -1\n\0"
 };
 
-// Unbuffered write to engine context.
-// 
-// The function definition for this depends on the PHP version used, and is
-// defined in the "_engine.h" file for the respective PHP version used.
-static ENGINE_UB_WRITE(str, len) {
+static int engine_ub_write(const char *str, uint len) {
 	engine_context *context = SG(server_context);
 
 	int written = engineWriteOut(context, (void *) str, len);
@@ -83,7 +79,7 @@ static sapi_module_struct engine_module = {
 	NULL,                        // Activate
 	NULL,                        // Deactivate
 
-	engine_ub_write,             // Unbuffered Write
+	engine_ub_write_proxy,       // Unbuffered Write
 	NULL,                        // Flush
 	NULL,                        // Get UID
 	NULL,                        // Getenv
@@ -139,3 +135,5 @@ void engine_shutdown(php_engine *engine) {
 	free(engine_module.ini_entries);
 	free(engine);
 }
+
+#include "_engine.c"

engine/include/php5/_engine.h

@@ -5,6 +5,6 @@
 #ifndef ___ENGINE_H___
 #define ___ENGINE_H___
 
-#define ENGINE_UB_WRITE(s, l) int engine_ub_write(const char *s, uint l)
+static int engine_ub_write_proxy(const char *str, uint len);
 
-#endif
+#endif

engine/include/php7/_engine.h

@@ -5,6 +5,6 @@
 #ifndef ___ENGINE_H___
 #define ___ENGINE_H___
 
-#define ENGINE_UB_WRITE(s, l) size_t engine_ub_write(const char *s, size_t l)
+static size_t engine_ub_write_proxy(const char *str, size_t len);
 
-#endif
+#endif

engine/php5.go

@@ -3,6 +3,6 @@
 package engine
 
 // #cgo CFLAGS: -I/usr/include/php5 -I/usr/include/php5/main -I/usr/include/php5/TSRM
-// #cgo CFLAGS: -I/usr/include/php5/Zend -Iinclude/php5
+// #cgo CFLAGS: -I/usr/include/php5/Zend -Iinclude/php5 -Isrc/php5
 // #cgo LDFLAGS: -lphp5
 import "C"

engine/php7.go

@@ -2,6 +2,6 @@
 
 package engine
 
-// #cgo CFLAGS: -Iinclude/php7
+// #cgo CFLAGS: -Iinclude/php7 -Isrc/php7
 // #cgo LDFLAGS: -lphp7
 import "C"

engine/src/php5/_engine.c

@@ -0,0 +1,7 @@
+// Copyright 2016 Alexander Palaistras. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+
+static int engine_ub_write_proxy(const char *str, uint len) {
+	return engine_ub_write(str, len);
+}

engine/src/php7/_engine.c

@@ -0,0 +1,7 @@
+// Copyright 2016 Alexander Palaistras. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+
+static size_t engine_ub_write_proxy(const char *str, size_t len) {
+	return engine_ub_write(str, len);
+}