cinap made some improvements that are worth adopting.
i'm redfaced that i saw tsemacquire, but missed semacquire and semrelease.

additionally, move the arches into a list and don't use patter matching.
we want exactly "seek" and "_SEEK".

Reference: /n/atom/patch/applied/truss64redux
Date: Sun Feb 16 13:56:17 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/lib/acid/syscall	Sun Feb 16 13:51:26 2014
+++ /sys/lib/acid/syscall	Sun Feb 16 13:51:27 2014
@@ -121,6 +121,8 @@
 	{34, {"rendezvous",	"AA",		code(*sysrendezvous:list)}},
 	{35, {"unmount",	"ss",		code(*sysunmount:list)}},
 	{36, {"_wait",		"A",		code(*sys_wait:list)}},
+	{37, {"semacquire",	"AD",		code(*syssemacquire:list)}},
+	{38, {"semrelease",	"AD",		code(*syssemrelease:list)}},
 	{39, {"seek",		"ADVD",		code(*sysseek:list)}},
 	{40, {"fversion",	"DDsD",		code(*sysfversion:list)}},
 	{41, {"errstr",		"TD",		code(*syserrstr:list)}},
--- /sys/lib/acid/truss	Sun Feb 16 13:51:28 2014
+++ /sys/lib/acid/truss	Sun Feb 16 13:51:28 2014
@@ -74,6 +74,8 @@
 		"brk_",
 		"remove",
 		"_wstat",
+		"semacquire",
+		"semrelease",
 		"_fwstat",
 		"notify",
 		"noted",
@@ -126,6 +128,8 @@
 		"_BRK_",
 		"_REMOVE",
 		"__WSTAT",
+		"_SEMACQUIRE",
+		"_SEMRELEASE",
 		"__FWSTAT",
 		"_NOTIFY",
 		"_NOTED",
@@ -150,11 +154,20 @@
 		"_TSEMACQUIRE",
 	};
 
+seekhackarch = {
+	"alpha",
+	"amd64",
+	"arm64",
+	"power64",
+};
+
 defn addressof(pattern) {
 	// translate to ape system calls if we have an ape binary
-	if _addressof("_EXITS") == 0 then
-		return _addressof(pattern);
-	return _addressof(trussapecalls[match(pattern, trusscalls)]);
+	if _addressof("_EXITS") != 0 then
+		pattern = trussapecalls[match(pattern, trusscalls)];
+	if (pattern == "seek" || pattern == "_SEEK") && match(objtype, seekhackarch) >= 0 then
+		pattern = "_" + pattern;
+	return _addressof(pattern);
 }
 
 defn setuptruss() {
@@ -167,8 +180,6 @@
 	{
 		name = head lst;
 		lst = tail lst;
-		if name == "seek" && (objtype=="amd64" || objtype == "power64" || objtype == "alpha") then
-			name = "_seek";
 		addr = addressof(name);
 		if addr then
 		{