Fix use-after-free in ppc64le's plt.c

Found by gcc 12

Resolves: #2046722

ltrace-0.7.91-W-use-after-free.patch

@@ -0,0 +1,13 @@
+diff -rup a/sysdeps/linux-gnu/ppc/plt.c b/sysdeps/linux-gnu/ppc/plt.c
+--- a/sysdeps/linux-gnu/ppc/plt.c	2022-01-27 20:40:52.956980433 -0500
++++ b/sysdeps/linux-gnu/ppc/plt.c	2022-01-27 20:41:37.031599771 -0500
+@@ -687,8 +687,8 @@ arch_elf_add_func_entry(struct process *
+ 		if (libsym == NULL
+ 		    || library_symbol_init(libsym, addr, full_name, 1,
+ 					   LS_TOPLT_NONE) < 0) {
+-			free(libsym);
+ 			delete_symbol_chain(libsym);
++			free(libsym);
+ 			libsym = NULL;
+ 			fprintf(stderr, "Couldn't add symbol %s"
+ 				"for tracing.\n", name);

ltrace.spec

@@ -1,7 +1,7 @@
 Summary: Tracks runtime library calls from dynamically linked executables
 Name: ltrace
 Version: 0.7.91
-Release: 43%{?dist}
+Release: 44%{?dist}
 # In coordination with Juan Céspedes, upstream is now officially on gitlab.
 # We are going to being sending all of our Fedora patches upstream to gitlab.
 URL: https://gitlab.com/cespedes/ltrace
@@ -132,6 +132,8 @@ Patch35: ltrace-0.7.91-rh1799619.patch
 # Support for both SC and SCV sycall insns
 Patch36: ltrace-0.7.91-ppc64le-scv.patch
 
+Patch37: ltrace-0.7.91-W-use-after-free.patch
+
 %description
 Ltrace is a debugging program which runs a specified command until the
 command exits.  While the command is executing, ltrace intercepts and
@@ -180,6 +182,7 @@ execution of processes.
 %patch34 -p1
 %patch35 -p1
 %patch36 -p1
+%patch37 -p1
 
 %build
 autoreconf -i
@@ -207,6 +210,9 @@ echo ====================TESTING END=====================
 %{_datadir}/ltrace
 
 %changelog
+* Thu Jan 27 2022 DJ Delorie <dj@redhat.com> - 0.7.91-44
+- Fix use-after-free cases.
+
 * Thu Jan 20 2022 Fedora Release Engineering <releng@fedoraproject.org> - 0.7.91-43
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_36_Mass_Rebuild