Turns out I wasn't building the syscall libraries. Do so.

plat/cpm/build-pkg.lua

@@ -19,7 +19,8 @@ installable {
 		"+tools",
 		"+libs",
         "./include+pkg",
-		["$(PLATIND)/cpm/boot.o"] = "+boot"
+		["$(PLATIND)/cpm/boot.o"] = "+boot",
+        ["$(PLATIND)/cpm/libsys.a"] = "./libsys+lib",
 	}
 }
 

plat/cpm/libsys/build.lua

@@ -0,0 +1,11 @@
+acklibrary {
+    name = "lib",
+    srcs = {
+        "./*.c",
+        "./*.s",
+    },
+    vars = {
+        plat = "cpm"
+    }
+}
+

plat/linux386/build-pkg.lua

@@ -18,7 +18,8 @@ installable {
 		"+tools",
 		"+libs",
 		"./include+pkg",
-		["$(PLATIND)/linux386/boot.o"] = "+boot"
+		["$(PLATIND)/linux386/boot.o"] = "+boot",
+        ["$(PLATIND)/linux386/libsys.a"] = "./libsys+lib",
 	}
 }
 

plat/linux386/descr

@@ -67,8 +67,7 @@ name led
 		(.ocm:{TAIL}={PLATFORMDIR}/liboccam.a) \
 		(.ocm.b.mod.c.p:{TAIL}={PLATFORMDIR}/libc.a) \
 		{FLOATS?} \
-		(.e:{TAIL}={PLATFORMDIR}/liblinux.a \
+		(.e:{TAIL}={PLATFORMDIR}/libem.a \
-		           {PLATFORMDIR}/libem.a \
 		           {PLATFORMDIR}/liblinux.a \
 		           {PLATFORMDIR}/libsys.a \
 		           {PLATFORMDIR}/libend.a)

plat/linux386/libsys/build.lua

@@ -0,0 +1,12 @@
+acklibrary {
+    name = "lib",
+    srcs = {
+        "./*.s",
+        "plat/linux/libsys/*.c",
+        "plat/linux/libsys/*.s",
+    },
+    vars = {
+        plat = "linux386"
+    }
+}
+

plat/pc86/build-pkg.lua

@@ -18,7 +18,8 @@ installable {
 		"+tools",
 		"+libs",
         "./include+pkg",
-		["$(PLATIND)/pc86/boot.o"] = "+boot"
+		["$(PLATIND)/pc86/boot.o"] = "+boot",
+        ["$(PLATIND)/pc86/libsys.a"] = "./libsys+lib",
 	}
 }
 

plat/pc86/libsys/build.lua

@@ -0,0 +1,11 @@
+acklibrary {
+    name = "lib",
+    srcs = {
+        "./*.c",
+        "./*.s",
+    },
+    vars = {
+        plat = "pc86"
+    }
+}
+