[newlib-cygwin] Cygwin: uname: fix building in non-git source dir

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=4949a82cde98886a79a962bf583cdbe9a2186078

commit 4949a82cde98886a79a962bf583cdbe9a2186078
Author:     Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Wed Dec 7 22:22:38 2022 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Wed Dec 7 22:22:38 2022 +0100

    Cygwin: uname: fix building in non-git source dir
    
    commit 97eb64b909bc broke building outside of a git dir, because
    the git describe command would fail.  Fix this by checking if
    we're in a git tree at all and just generate an empty string
    as version string.  Use this in uname_x to generate a fallback
    version.
    
    Fixes: 97eb64b909bc ("Cygwin: uname: generate default release
    string from git as well"
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/Makefile.am |  5 ++++-
 winsup/cygwin/uname.cc    | 12 ++++++++++--
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/Makefile.am b/winsup/cygwin/Makefile.am
index b1849d5a6737..e61f72716e10 100644
--- a/winsup/cygwin/Makefile.am
+++ b/winsup/cygwin/Makefile.am
@@ -421,7 +421,10 @@ src_files := $(foreach dir,$(dirs),$(find_src_files))
 
 uname_version.c: .FORCE
 	$(AM_V_GEN)cd $(srcdir) && \
-	echo "const char *uname_dev_version = \"$$(git describe --dirty | sed -e 's/cygwin-//')\";" > $(abs_builddir)/uname_version.c
+	echo "const char *uname_dev_version = \
+	\"$$(git rev-parse --git-dir >/dev/null 2>&1 && \
+	     git describe --dirty | sed -e 's/cygwin-//')\";" \
+	     > $(abs_builddir)/uname_version.c
 .FORCE:
 
 # mkvers.sh creates version.cc in the first place, winver.o always
diff --git a/winsup/cygwin/uname.cc b/winsup/cygwin/uname.cc
index d2f93304e494..dd4160189c3a 100644
--- a/winsup/cygwin/uname.cc
+++ b/winsup/cygwin/uname.cc
@@ -60,8 +60,16 @@ uname_x (struct utsname *name)
 		__XSTRING (CYGPORT_RELEASE_INFO), name->machine);
 #else
       extern const char *uname_dev_version;
-      snprintf (name->release, _UTSNAME_LENGTH, "%s.%s",
-		uname_dev_version, name->machine);
+      if (uname_dev_version && uname_dev_version[0])
+	snprintf (name->release, _UTSNAME_LENGTH, "%s.%s",
+		  uname_dev_version, name->machine);
+      else
+	__small_sprintf (name->release, "%d.%d.%d-api-%d.%s",
+			 cygwin_version.dll_major / 1000,
+			 cygwin_version.dll_major % 1000,
+			 cygwin_version.dll_minor,
+			 cygwin_version.api_minor,
+			 name->machine);
 #endif
 #pragma GCC diagnostic pop
       /* version */