Changed error(...) to a weak function

Made error(...) a weak function so that it can be overridden in
production projects. Also fixed several serial_api.c files that required
stdlib.h, but were getting it from error.h.

libraries/mbed/api/error.h

@@ -53,14 +53,16 @@
  * #endcode
  */
 
-#include <stdlib.h>
-#include "device.h"
+#include "toolchain.h"
 
-#if DEVICE_STDIO_MESSAGES
-    #include <stdio.h>
-    #define error(...) (fprintf(stderr, __VA_ARGS__), exit(1))
-#else
-    #define error(...) (exit(1))
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void error(const char* format, ...);
+
+#ifdef __cplusplus
+}
 #endif
 
 #endif

libraries/mbed/common/error.c

@@ -0,0 +1,33 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <stdlib.h>
+#include <stdarg.h>
+#include "device.h"
+#include "toolchain.h"
+#if DEVICE_STDIO_MESSAGES
+#include <stdio.h>
+#endif
+
+WEAK void error(const char* format, ...);
+WEAK void error(const char* format, ...) {
+#if DEVICE_STDIO_MESSAGES
+    va_list arg;
+    va_start(arg, format);
+    vfprintf(stderr, format, arg);
+    va_end(arg);
+#endif
+    exit(1);
+}

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11UXX/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC176X/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC23XX/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC408X/serial_api.c

@@ -16,6 +16,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"

libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC43XX/serial_api.c

@@ -18,6 +18,7 @@
 // math.h required for floating point operations for baud rate calculation
 #include <math.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "serial_api.h"
 #include "cmsis.h"