libf2fs: fix build error on Windows

Windows doesn't support S_ISREG, so let's avoid depedency.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Change-Id: I9188dc02e6e2f03a0091892bb7e554b350da3070
diff --git a/include/f2fs_fs.h b/include/f2fs_fs.h
index 265f50c..709bfd8 100644
--- a/include/f2fs_fs.h
+++ b/include/f2fs_fs.h
@@ -1178,6 +1178,10 @@
 	F2FS_FT_LAST_FILE_TYPE = F2FS_FT_XATTR,
 };
 
+#define LINUX_S_IFMT  00170000
+#define LINUX_S_IFREG  0100000
+#define LINUX_S_ISREG(m)	(((m) & LINUX_S_IFMT) == LINUX_S_IFREG)
+
 /* from f2fs/segment.h */
 enum {
 	LFS = 0,
diff --git a/lib/libf2fs.c b/lib/libf2fs.c
index c2960fd..55d3a5c 100644
--- a/lib/libf2fs.c
+++ b/lib/libf2fs.c
@@ -504,7 +504,7 @@
 {
 	unsigned int addrs = CUR_ADDRS_PER_INODE(i) - get_inline_xattr_addrs(i);
 
-	if (!S_ISREG(le16_to_cpu(i->i_mode)) ||
+	if (!LINUX_S_ISREG(le16_to_cpu(i->i_mode)) ||
 			!(le32_to_cpu(i->i_flags) & F2FS_COMPR_FL))
 		return addrs;
 	return ALIGN_DOWN(addrs, 1 << i->i_log_cluster_size);
@@ -512,7 +512,7 @@
 
 unsigned int addrs_per_block(struct f2fs_inode *i)
 {
-	if (!S_ISREG(le16_to_cpu(i->i_mode)) ||
+	if (!LINUX_S_ISREG(le16_to_cpu(i->i_mode)) ||
 			!(le32_to_cpu(i->i_flags) & F2FS_COMPR_FL))
 		return DEF_ADDRS_PER_BLOCK;
 	return ALIGN_DOWN(DEF_ADDRS_PER_BLOCK, 1 << i->i_log_cluster_size);