fix building C

build.ce

@@ -106,7 +106,7 @@ if (target_package) {
   _build = function() {
     lib = build.build_dynamic(target_package, target, buildtype)
     if (lib) {
-      log.console('Built: ' + lib)
+      log.console(`Built ${text(length(lib))} module(s)`)
     }
   } disruption {
     log.error('Build failed')

build.cm

@@ -105,22 +105,23 @@ Build.compile_file = function(pkg, file, target, buildtype) {
   var _buildtype = buildtype || 'release'
   var pkg_dir = shop.get_package_dir(pkg)
   var src_path = pkg_dir + '/' + file
+  var core_dir = null
 
   if (!fd.is_file(src_path)) {
     print('Source file not found: ' + src_path); disrupt
   }
-  
+
   // Get flags (with sigil replacement)
   var cflags = replace_sigils_array(pkg_tools.get_flags(pkg, 'CFLAGS', target))
   var target_cflags = toolchains[target].c_args || []
   var cc = toolchains[target].c
-  
+
   // Symbol name for this file
   var sym_name = shop.c_symbol_for_file(pkg, file)
-  
+
   // Build command
   var cmd_parts = [cc, '-c', '-fPIC']
-  
+
   // Add buildtype-specific flags
   if (_buildtype == 'release') {
     cmd_parts = array(cmd_parts, ['-O3', '-DNDEBUG'])
@@ -129,10 +130,16 @@ Build.compile_file = function(pkg, file, target, buildtype) {
   } else if (_buildtype == 'minsize') {
     cmd_parts = array(cmd_parts, ['-Os', '-DNDEBUG'])
   }
-  
+
   push(cmd_parts, '-DCELL_USE_NAME=' + sym_name)
   push(cmd_parts, '-I"' + pkg_dir + '"')
-  
+
+  // External packages need core's source dir for cell.h, quickjs.h, blob.h
+  if (pkg != 'core') {
+    core_dir = shop.get_package_dir('core')
+    push(cmd_parts, '-I"' + core_dir + '/source"')
+  }
+
   // Add package CFLAGS (resolve relative -I paths)
   arrfor(cflags, function(flag) {
     var f = flag
@@ -221,9 +228,11 @@ function compute_link_key(objects, ldflags, target_ldflags, opts) {
 
 // Build a per-module dynamic library for a single C file
 // Returns the content-addressed dylib path in .cell/build/<hash>.<target>.dylib
-Build.build_module_dylib = function(pkg, file, target, buildtype) {
+Build.build_module_dylib = function(pkg, file, target, opts) {
+  var _opts = opts || {}
   var _target = target || Build.detect_host_target()
-  var _buildtype = buildtype || 'release'
+  var _buildtype = _opts.buildtype || 'release'
+  var _extra = _opts.extra_objects || []
   var obj = Build.compile_file(pkg, file, _target, _buildtype)
 
   var tc = toolchains[_target]
@@ -244,8 +253,10 @@ Build.build_module_dylib = function(pkg, file, target, buildtype) {
     push(resolved_ldflags, f)
   })
 
-  // Content-addressed output: hash of (object + link flags + target)
-  var link_key = compute_link_key([obj], resolved_ldflags, target_ldflags, {target: _target, cc: cc})
+  // Content-addressed output: hash of (all objects + link flags + target)
+  var all_objects = [obj]
+  all_objects = array(all_objects, _extra)
+  var link_key = compute_link_key(all_objects, resolved_ldflags, target_ldflags, {target: _target, cc: cc})
   var build_dir = get_build_dir()
   ensure_dir(build_dir)
   var dylib_path = build_dir + '/' + link_key + '.' + _target + dylib_ext
@@ -275,6 +286,9 @@ Build.build_module_dylib = function(pkg, file, target, buildtype) {
 
   push(cmd_parts, '-L"' + local_dir + '"')
   push(cmd_parts, '"' + obj + '"')
+  arrfor(_extra, function(extra_obj) {
+    push(cmd_parts, '"' + extra_obj + '"')
+  })
   cmd_parts = array(cmd_parts, resolved_ldflags)
   cmd_parts = array(cmd_parts, target_ldflags)
   push(cmd_parts, '-o')
@@ -288,7 +302,10 @@ Build.build_module_dylib = function(pkg, file, target, buildtype) {
   }
 
   // Install to deterministic lib/<pkg>/<stem>.dylib
+  // Strip .c/.cpp extension so the loader can find it by module name
   var file_stem = file
+  if (ends_with(file_stem, '.cpp')) file_stem = text(file_stem, 0, -4)
+  else if (ends_with(file_stem, '.c')) file_stem = text(file_stem, 0, -2)
   var install_dir = shop.get_lib_dir() + '/' + shop.lib_name_for_package(pkg)
   var stem_dir = fd.dirname(file_stem)
   if (stem_dir && stem_dir != '.') {
@@ -310,9 +327,17 @@ Build.build_dynamic = function(pkg, target, buildtype) {
   var c_files = pkg_tools.get_c_files(pkg, _target, true)
   var results = []
 
+  // Compile support sources to cached objects
+  var sources = pkg_tools.get_sources(pkg)
+  var support_objects = []
+  arrfor(sources, function(src_file) {
+    var obj = Build.compile_file(pkg, src_file, _target, _buildtype)
+    push(support_objects, obj)
+  })
+
   arrfor(c_files, function(file) {
     var sym_name = shop.c_symbol_for_file(pkg, file)
-    var dylib = Build.build_module_dylib(pkg, file, _target, _buildtype)
+    var dylib = Build.build_module_dylib(pkg, file, _target, {buildtype: _buildtype, extra_objects: support_objects})
     push(results, {file: file, symbol: sym_name, dylib: dylib})
   })
 

docs/c-modules.md

@@ -244,6 +244,20 @@ audio_emscripten.c # Web/Emscripten
 
 ƿit selects the appropriate file based on the target platform.
 
+## Multi-File C Modules
+
+If your module wraps a C library, place the library's source files in a `src/` directory. Files in `src/` are compiled as support objects and linked into your module's dylib — they are not treated as standalone modules.
+
+```
+mypackage/
+  rtree.c       # module (exports js_mypackage_rtree_use)
+  src/
+    rtree.c      # support file (linked into rtree.dylib)
+    rtree.h      # header
+```
+
+The module file (`rtree.c`) includes the library header and uses `cell.h` as usual. The support files are plain C — they don't need any cell macros.
+
 ## Static Declarations
 
 Keep internal functions and variables `static`:

internal/shop.cm

@@ -713,14 +713,14 @@ function make_c_symbol(pkg, file) {
   return 'js_' + pkg_id + '_' + file_safe + '_use'
 }
 
-// Get the deterministic dylib path for a module in lib/<pkg>/<stem>.dylib
+// Get the deterministic dylib path for a module in lib/<pkg_id>/<stem>.dylib
 function get_dylib_path(pkg, stem) {
-  return global_shop_path + '/lib/' + safe_package_path(pkg) + '/' + stem + dylib_ext
+  return global_shop_path + '/lib/' + get_package_id(pkg) + '/' + stem + dylib_ext
 }
 
-// Get the deterministic mach path for a module in lib/<pkg>/<stem>.mach
+// Get the deterministic mach path for a module in lib/<pkg_id>/<stem>.mach
 function get_mach_path(pkg, stem) {
-  return global_shop_path + '/lib/' + safe_package_path(pkg) + '/' + stem + '.mach'
+  return global_shop_path + '/lib/' + get_package_id(pkg) + '/' + stem + '.mach'
 }
 
 // Open a per-module dylib and return the dlopen handle

package.cm

@@ -379,10 +379,26 @@ package.get_c_files = function(name, target, exclude_main) {
       push(result, selected)
     }
   })
-  
+
+  // Exclude src/ files (support files, not modules)
+  var sources = package.get_sources(name)
+  if (length(sources) > 0) {
+    result = filter(result, function(f) {
+      return find(sources, function(s) { return s == f }) == null
+    })
+  }
+
   return result
 }
 
+// Get support source files: C files in src/ directories (not modules)
+package.get_sources = function(name) {
+  var files = package.list_files(name)
+  return filter(files, function(f) {
+    return (ends_with(f, '.c') || ends_with(f, '.cpp')) && starts_with(f, 'src/')
+  })
+}
+
 // Get the absolute path for a package
 package.get_dir = function(name) {
   return get_path(name)