sys-process/forkstat: add -r support for musl

Closed as WONTFIX upstream, but the patch is simple enough and email
threads linked on the bug (incluing by glibc developers) say there should
be no functional difference.

Bug: https://github.com/ColinIanKing/forkstat/issues/1
Signed-off-by: Carlos Eduardo <carana2099@gmail.com>

sys-process/forkstat/files/musl-prio.patch

@@ -0,0 +1,21 @@
+diff --git a/forkstat.c b/forkstat.c
+index 57dc9c8..4b22c42 100644
+--- a/forkstat.c
++++ b/forkstat.c
+@@ -40,6 +40,7 @@
+ #include <time.h>
+ #include <getopt.h>
+ #include <sched.h>
++#include <pthread.h>
+ #include <pwd.h>
+ 
+ #include <sys/ioctl.h>
+@@ -2022,7 +2023,7 @@ int main(int argc, char * const argv[])
+ 
+ 		(void)memset(&param, 0, sizeof(param));
+ 		param.sched_priority = max_prio;
+-		if (sched_setscheduler(getpid(), policy, &param) < 0) {
++		if (pthread_setschedparam(pthread_self(), policy, &param) < 0) {
+ 			(void)fprintf(stderr, "sched_setscheduler failed: errno=%d (%s)\n",
+ 				errno, strerror(errno));
+ 			goto abort_sock;

sys-process/forkstat/forkstat-0.03.02-r2.ebuild

@@ -12,7 +12,7 @@ S="${WORKDIR}/${P}"
 LICENSE="GPL-2"
 SLOT="0"
 KEYWORDS="~amd64"
-
+PATCHES=( "${FILESDIR}/musl-prio.patch" )
 src_prepare() {
 	default
 	sed -i 's/8.gz/8/g' Makefile