Android NDK: __errno is already defined as a function

criu/log.c:356:16: error: called object type 'int' is not a function or function pointer
        int __errno = errno;
                      ^~~~~
/root/android-ndk/toolchains/llvm/prebuilt/linux-x86_64//sysroot/usr/include/errno.h:43:24: note: expanded from macro 'errno'
                ~~~~~~~^
criu/log.c:391:2: error: called object type 'int' is not a function or function pointer
        errno =  __errno;
        ^~~~~
/root/android-ndk/toolchains/llvm/prebuilt/linux-x86_64//sysroot/usr/include/errno.h:43:24: note: expanded from macro 'errno'

in Android NDK's errno.h:

42: int* __errno(void) __attribute_const__;
43: #define errno (*__errno())

so rename __errno to _errno to pass build

Cc: Chen Hu <hu1.chen@intel.com>
Signed-off-by: Zhang Ning <ning.a.zhang@intel.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

criu/log.c

@@ -353,7 +353,7 @@ static void early_vprint(const char *format, unsigned int loglevel, va_list para
 void vprint_on_level(unsigned int loglevel, const char *format, va_list params)
 {
 	int fd, size, ret, off = 0;
-	int __errno = errno;
+	int _errno = errno;
 
 	if (unlikely(loglevel == LOG_MSG)) {
 		fd = STDOUT_FILENO;
@@ -388,7 +388,7 @@ void vprint_on_level(unsigned int loglevel, const char *format, va_list params)
 	if (loglevel == LOG_ERROR)
 		log_note_err(buffer + buf_off);
 
-	errno =  __errno;
+	errno =  _errno;
 }
 
 void print_on_level(unsigned int loglevel, const char *format, ...)

test/zdtm/lib/msg.c

@@ -40,7 +40,7 @@ void test_msg(const char *format, ...)
 	va_list arg;
 	int off = 0;
 	char buf[TEST_MSG_BUFFER_SIZE];
-	int __errno = errno;
+	int _errno = errno;
 	struct timeval tv;
 	struct tm *tm;
 
@@ -65,5 +65,5 @@ skip:
 	va_end(arg);
 
 	write(2, buf, off);
-	errno = __errno;
+	errno = _errno;
 }