diff --git a/build.cc b/build.cc
index 52dd08f..8218029 100644
--- a/build.cc
+++ b/build.cc
@@ -37,7 +37,7 @@ static std::vector<std::string> EXAMPLES = {
     "stream1", "stream2", "coroutine1", "coroutine2", "concurrency"
 };
 
-static fs::path ASM_SOURCE_DIR = "src/asm";
+static fs::path ASM_SOURCE_DIR = fs::path{"src"} / "asm";
 static strvec ASM_SOURCES = {
     "jump_all_gas", "make_all_gas", "ontop_all_gas"
 };
diff --git a/src/process.cc b/src/process.cc
index a1226c2..8657229 100644
--- a/src/process.cc
+++ b/src/process.cc
@@ -479,21 +479,22 @@ static std::string concat_args(std::vector<std::string> const &args) {
             if (*p == '\"') {
                 /* not preceded by \, so it's safe */
                 ret += "\\\"";
+                ++p;
             } else {
                 /* handle any sequence of \ optionally followed by a " */
-                std::size_t nbsl = 0;
-                while (*p++ == '\\') {
-                    ++nbsl;
+                char const *op = p;
+                while (*p == '\\') {
+                    ++p;
                 }
                 if (*p == '\"') {
                     /* double all the backslashes plus one for the " */
-                    ret.append(nbsl * 2 + 1, '\\');
+                    ret.append((p - op) * 2 + 1, '\\');
                     ret += '\"';
                 } else {
-                    ret.append(nbsl, '\\');
+                    ret.append(p - op, '\\');
                 }
             }
-            sp = p + 1;
+            sp = p;
         }
         ret += '\"';
     }