app-text/opensp: fix build on musl

fix error below:

> dcigettext.c:154:7: error: conflicting types for 'getcwd'; have 'char *(void)'
>   154 | char *getcwd ();
>       |       ^~~~~~

Closes: https://bugs.gentoo.org/947175
Signed-off-by: Z. Liu <zhixu.liu@gmail.com>
Part-of: https://github.com/gentoo/gentoo/pull/45199
Signed-off-by: Sam James <sam@gentoo.org>

app-text/opensp/files/opensp-1.5.2-gcc15-musl.patch

@@ -0,0 +1,19 @@
+fix error on musl:
+
+dcigettext.c:154:7: error: conflicting types for 'getcwd'; have 'char *(void)'
+  154 | char *getcwd ();
+      |       ^~~~~~
+
+diff --git a/intl/dcigettext.c b/intl/dcigettext.c
+index c7f4506..9dad6c4 100644
+--- a/intl/dcigettext.c
++++ b/intl/dcigettext.c
+@@ -151,7 +151,7 @@ char *getwd ();
+ #  if VMS
+ #   define getcwd(buf, max) (getcwd) (buf, max, 0)
+ #  else
+-char *getcwd ();
++char *getcwd (char *, size_t);
+ #  endif
+ # endif
+ # ifndef HAVE_STPCPY

app-text/opensp/opensp-1.5.2-r10.ebuild

@@ -35,6 +35,7 @@ PATCHES=(
 	"${FILESDIR}"/${P}-c11-using.patch
 	"${FILESDIR}"/${P}-configure-clang16.patch
 	"${FILESDIR}"/${P}-fix-ar-intl.patch
+	"${FILESDIR}"/${P}-gcc15-musl.patch
 )
 
 src_prepare() {