Fix newlib build failure

Starting with upstream newlib commit
492e5fe8b0863e15ffd5a269e42b60fabfc5f5db newlib build started failing
on machine that don't have makeinfo (part of texinfo package)
installed when trying to build the file libgloss/doc/porting.info.

We don't provide newlib docs as part of our distribution, so makeinfo
should not be required. This patch fixes the issue by creating an
empty libgloss/doc/porting.info file.

Author: miyuki

patches/newlib-HEAD.patch

@@ -25,7 +25,7 @@ index 6b2d62a9b..000a2c728 100644
  #endif
  {
 diff --git a/libgloss/arm/syscalls.c b/libgloss/arm/syscalls.c
-index fc394f94b..0b3287df4 100644
+index 710a741ee..9e710b09a 100644
 --- a/libgloss/arm/syscalls.c
 +++ b/libgloss/arm/syscalls.c
 @@ -180,7 +180,7 @@ initialise_monitor_handles (void)
@@ -67,6 +67,13 @@ index 845ad0173..2056c2adf 100644
          .global __rt_stkovf_split_big
          .global __rt_stkovf_split_small
 
+diff --git a/libgloss/doc/porting.info b/libgloss/doc/porting.info
+new file mode 100644
+index 000000000..8b1378917
+--- /dev/null
++++ b/libgloss/doc/porting.info
+@@ -0,0 +1 @@
++
 diff --git a/newlib/libc/machine/aarch64/memchr.S b/newlib/libc/machine/aarch64/memchr.S
 index 53f5d6bc0..81fcecccd 100644
 --- a/newlib/libc/machine/aarch64/memchr.S

versions.yml

@@ -55,5 +55,5 @@ Revisions:
       - Name: newlib.git
         FriendlyName: Newlib
         URL:  https://github.com/mirror/newlib-cygwin.git
-        Revision: d5a20f0b70c73c72ec2bc4b639815bb821859255
+        Revision: 492e5fe8b0863e15ffd5a269e42b60fabfc5f5db
         Patch: newlib-HEAD.patch