Convert strdup.c to C++.

src/system/boot/Jamfile

@@ -21,7 +21,7 @@ BootMergeObject boot_libroot.o :
 	memchr.c
 	memcmp.c
 	memmove.c
-	strdup.c
+	strdup.cpp
 	strndup.cpp
 	strlen.cpp
 	strnlen.cpp

src/system/kernel/lib/Jamfile

@@ -107,7 +107,7 @@ KernelMergeObject kernel_lib_posix.o :
 	strcmp.c
 	strcpy.c
 	strcspn.c
-	strdup.c
+	strdup.cpp
 	strerror.c
 	strlcat.c
 	strlcpy.c

src/system/libroot/posix/string/Jamfile

@@ -5,6 +5,12 @@ UsePrivateHeaders
 	[ FDirName libroot locale ]
 	;
 
+
+# Our versions of strdup and strndup check for NULL parameters (for BeOS
+# compatibility), but GCC optimizes this away as its builtins don't handle
+# it.
+C++FLAGS += -fno-builtin-strdup -fno-builtin-strndup ;
+
 local architectureObject ;
 for architectureObject in [ MultiArchSubDirSetup ] {
 	on $(architectureObject) {
@@ -29,7 +35,7 @@ for architectureObject in [ MultiArchSubDirSetup ] {
 			strcoll.cpp
 			strcpy.c
 			strcspn.c
-			strdup.c
+			strdup.cpp
 			strerror.c
 			strlcat.c
 			strlcpy.c

src/system/libroot/posix/string/strdup.c

@@ -1,29 +0,0 @@
-/* 
- * Copyright 2003-2007, Axel Dörfler, [email protected]. All rights reserved.
- * Distributed under the terms of the MIT License.
- */
-
-
-#include <string.h>
-#include <stdlib.h>
-
-
-char*
-strdup(const char *string)
-{
-	char* copied;
-	size_t length;
-
-	// unlike the standard strdup() function, the BeOS implementation
-	// handles NULL strings gracefully
-	if (string == NULL)
-		return NULL;
-
-	length = strlen(string) + 1;
-
-	if ((copied = (char *)malloc(length)) == NULL)
-		return NULL;
-
-	memcpy(copied, string, length);
-	return copied;
-}