diff --git a/BRANCH_TODO b/BRANCH_TODO
index 096207a4cf..d3a2ac8f90 100644
--- a/BRANCH_TODO
+++ b/BRANCH_TODO
@@ -1,6 +1,5 @@
- * add CLI support for a way to pass extra flags to c source files
- * musl
  * support rpaths in ELF linker code
+ * musl
  * implement proper parsing of LLD stderr/stdout and exposing compile errors
  * tests passing with -Dskip-non-native
  * windows CUSTOMBUILD : error : unable to build compiler_rt: FileNotFound [D:\a\1\s\build\zig_install_lib_files.vcxproj]
diff --git a/lib/std/build.zig b/lib/std/build.zig
index 133919afc1..7499b40533 100644
--- a/lib/std/build.zig
+++ b/lib/std/build.zig
@@ -1947,6 +1947,7 @@ pub const LibExeObjStep = struct {
 
         if (self.root_src) |root_src| try zig_args.append(root_src.getPath(builder));
 
+        var prev_has_extra_flags = false;
         for (self.link_objects.span()) |link_object| {
             switch (link_object) {
                 .StaticPath => |static_path| {
@@ -1979,12 +1980,26 @@ pub const LibExeObjStep = struct {
                     try zig_args.append(name);
                 },
                 .AssemblyFile => |asm_file| {
+                    if (prev_has_extra_flags) {
+                        try zig_args.append("-extra-cflags");
+                        try zig_args.append("--");
+                        prev_has_extra_flags = false;
+                    }
                     try zig_args.append(asm_file.getPath(builder));
                 },
                 .CSourceFile => |c_source_file| {
-                    try zig_args.append("--c-source");
-                    for (c_source_file.args) |arg| {
-                        try zig_args.append(arg);
+                    if (c_source_file.args.len == 0) {
+                        if (prev_has_extra_flags) {
+                            try zig_args.append("-cflags");
+                            try zig_args.append("--");
+                            prev_has_extra_flags = false;
+                        }
+                    } else {
+                        try zig_args.append("-cflags");
+                        for (c_source_file.args) |arg| {
+                            try zig_args.append(arg);
+                        }
+                        try zig_args.append("--");
                     }
                     try zig_args.append(c_source_file.source.getPath(builder));
                 },
diff --git a/src/main.zig b/src/main.zig
index 1873656e77..73676fb75e 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -244,6 +244,7 @@ const usage_build_generic =
     \\  -I[dir]                   Add directory to include search path
     \\  -D[macro]=[value]         Define C [macro] to [value] (1 if [value] omitted)
     \\  --libc [file]             Provide a file which specifies libc paths
+    \\  -cflags [flags] --        Set extra flags for the next positional C source files
     \\
     \\Link Options:
     \\  -l[lib], --library [lib]       Link against system library
@@ -376,6 +377,9 @@ pub fn buildOutputType(
     var clang_argv = std.ArrayList([]const u8).init(gpa);
     defer clang_argv.deinit();
 
+    var extra_cflags = std.ArrayList([]const u8).init(gpa);
+    defer extra_cflags.deinit();
+
     var lld_argv = std.ArrayList([]const u8).init(gpa);
     defer lld_argv.deinit();
 
@@ -469,6 +473,14 @@ pub fn buildOutputType(
                         if (i + 1 >= args.len) fatal("expected parameter after {}", .{arg});
                         i += 1;
                         main_pkg_path = args[i];
+                    } else if (mem.eql(u8, arg, "-cflags")) {
+                        extra_cflags.shrinkRetainingCapacity(0);
+                        while (true) {
+                            i += 1;
+                            if (i + 1 >= args.len) fatal("expected -- after -cflags", .{});
+                            if (mem.eql(u8, args[i], "--")) break;
+                            try extra_cflags.append(args[i]);
+                        }
                     } else if (mem.eql(u8, arg, "--color")) {
                         if (i + 1 >= args.len) {
                             fatal("expected [auto|on|off] after --color", .{});
@@ -713,8 +725,10 @@ pub fn buildOutputType(
                         try link_objects.append(arg);
                     },
                     .assembly, .c, .cpp, .h, .ll, .bc => {
-                        // TODO a way to pass extra flags on the CLI
-                        try c_source_files.append(.{ .src_path = arg });
+                        try c_source_files.append(.{
+                            .src_path = arg,
+                            .extra_flags = try arena.dupe([]const u8, extra_cflags.items),
+                        });
                     },
                     .shared_library => {
                         fatal("linking against dynamic libraries not yet supported", .{});