Grrhh! Sorry! Had diff arguments in reverse orders.
root@kibar:~/procps-3.3.16# diff -u ../orig/procps-3.3.16/pgrep.c pgrep.c
--- ../orig/procps-3.3.16/pgrep.c 2020-02-06 06:04:02.000000000 -0500
+++ pgrep.c 2021-02-02 11:39:44.000000000 -0500
@@ -498,6 +498,8 @@
pid_t myself = getpid();
struct el *list = NULL;
long cmdlen = sysconf(_SC_ARG_MAX) * sizeof(char);
+ if (cmdlen==-1) // sysconf returned "no limitations"
+ cmdlen=1000; // 1000 chars (arbitrary value)
char *cmdline = xmalloc(cmdlen);
char *cmdsearch = xmalloc(cmdlen);
char *cmdoutput = xmalloc(cmdlen);
root@kibar:~/procps-3.3.16#