dev-libs/nspr: remove unused patch

Closes: https://github.com/gentoo/gentoo/pull/6215

dev-libs/nspr/files/nspr-4.15-configure_in.patch

@@ -1,26 +0,0 @@
-From 9c751b2e857db1760d2fa82d9c20e7da518a5da7 Mon Sep 17 00:00:00 2001
-From: "Jory A. Pratt" <anarchy@gentoo.org>
-Date: Wed, 7 Jun 2017 12:14:46 -0500
-Subject: [PATCH] Close out darwin if statement, will breakage configure.in
- rename to configure.ac
-
-Signed-off-by: Jory A. Pratt <anarchy@gentoo.org>
----
- configure.in | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/configure.in b/configure.in
-index 4b2e46d..dc14ee5 100644
---- a/configure.in
-+++ b/configure.in
-@@ -1389,6 +1389,7 @@ case "$target" in
-     changequote([,])
-     if test "$HOST_DARWIN_MAJOR" -ge 15 ; then
-         AC_DEFINE(HAS_CONNECTX)
-+    fi
-     AS='$(CC) -x assembler-with-cpp'
-     CFLAGS="$CFLAGS -Wall -fno-common"
-     case "${target_cpu}" in
--- 
-2.13.1
-