thumbv6m: don't remove symbols that weren't added

Author: Jorge Aparicio

build.rs

@@ -383,8 +383,8 @@ fn main() {
 
         // Remove the assembly implementations that won't compile for the target
         if llvm_target[0] == "thumbv6m" {
-            sources.remove(&["aeabi_cdcmp", "aeabi_cfcmp", "aeabi_dcmp", "aeabi_fcmp", "aeabi_ldivmod",
-                            "aeabi_memset", "aeabi_uldivmod", "clzdi2", "clzsi2", "comparesf2",
+            sources.remove(&["aeabi_cdcmp", "aeabi_cfcmp", "aeabi_dcmp", "aeabi_fcmp",
+                            "clzdi2", "clzsi2", "comparesf2",
                             "divmodsi4", "divsi3", "modsi3", "switch16", "switch32", "switch8",
                             "switchu8", "udivmodsi4", "udivsi3", "umodsi3"]);