diff --git a/build_tool/easy_strings.cpp b/build_tool/easy_strings.cpp
index 59e9de5..128c25c 100644
--- a/build_tool/easy_strings.cpp
+++ b/build_tool/easy_strings.cpp
@@ -36,10 +36,8 @@ Array<S8_String> &operator+=(Array<S8_String> &a, S8_String s) {
 }
 
 //@todo: split on any whitespace instead!
-Array<S8_String> Split(char *str) {
-    S8_String s = S8_MakeFromChar(str);
-    S8_List list = S8_Split(Perm, s, S8_Lit(" "), 0);
-
+Array<S8_String> Split(S8_String s, S8_String sep = " ") {
+    S8_List list = S8_Split(Perm, s, sep, 0);
     Array<S8_String> result = {*Perm};
     S8_For(it, list) result.add(it->string);
     return result;
diff --git a/build_tool/main.cpp b/build_tool/main.cpp
index 007247c..6793b7a 100644
--- a/build_tool/main.cpp
+++ b/build_tool/main.cpp
@@ -58,6 +58,7 @@ int main(int argument_count, char **arguments) {
             flags += "-Wno-writable-strings";
             flags += "-fno-exceptions";
             flags += "-fno-rtti";
+            flags += "-lm";
             flags += Fmt("-o %.*s", S8_Expand(exe_name));
             result = Run(cc + build_file + flags);
         }
@@ -69,6 +70,7 @@ int main(int argument_count, char **arguments) {
             flags += "-Wno-write-strings";
             flags += "-fno-exceptions";
             flags += "-fno-rtti";
+            flags += "-lm";
             flags += Fmt("-o %.*s", S8_Expand(exe_name));
             result = Run(cc + build_file + flags);
         }
diff --git a/standalone_libraries/string.c b/standalone_libraries/string.c
index f13a363..a9ab569 100644
--- a/standalone_libraries/string.c
+++ b/standalone_libraries/string.c
@@ -328,7 +328,7 @@ S8_API S8_String S8_MergeWithSeparator(S8_Allocator allocator, S8_List list, S8_
     int64_t base_size = (list.char_count + 1);
     int64_t sep_size = (list.node_count - 1) * separator.len;
     int64_t size = base_size + sep_size;
-    char *buff = (char *)S8_ALLOCATE(allocator, sizeof(char) * size);
+    char *buff = (char *)S8_ALLOCATE(allocator, sizeof(char) * (size + 1));
     S8_String string = S8_Make(buff, 0);
     for (S8_Node *it = list.first; it; it = it->next) {
         S8_ASSERT(string.len + it->string.len <= size);
diff --git a/standalone_libraries/string.h b/standalone_libraries/string.h
index 4a71c5c..37ef01d 100644
--- a/standalone_libraries/string.h
+++ b/standalone_libraries/string.h
@@ -2,6 +2,7 @@
 #define FIRST_S8_STRING
 #include <stdint.h>
 #include <stdbool.h>
+#include <stdarg.h>
 
 #ifndef S8_API
     #define S8_API