waflib: Add check_cxx_decl() and check_c_decl()

demos/c++/wscript

@@ -16,6 +16,7 @@ def options(opt):
 def configure(conf):
 	conf.load('compiler_cxx')
 	conf.check(header_name='stdio.h', features='cxx cxxprogram', mandatory=False)
+	conf.check_cxx_decl('memcpy(void *, const void *, size_t)', header_name='string.h')
 	conf.check_cxx_func('memcpy')
 
 def build(bld):

demos/c/wscript

@@ -41,6 +41,7 @@ def configure(conf):
 	conf.check(lib='m', cflags='-Wall', defines=['var=foo', 'x=y'], uselib_store='M', mandatory=False)
 	conf.check_large_file(mandatory=False)
 	conf.check_inline()
+	conf.check_c_decl('memcpy(void *, const void *, size_t)', header_name='string.h')
 	conf.check_c_func('memcpy')
 
 	endianness = conf.check_endianness()

docs/sphinx/confmap.rst

@@ -33,6 +33,10 @@ Configuration methods
 
 * check_
 
+.. _check_c_decl: tools/c_config.html#waflib.Tools.c_config.check_c_decl
+
+* check_c_decl_
+
 .. _check_c_func: tools/c_config.html#waflib.Tools.c_config.check_c_func
 
 * check_c_func_
@@ -49,6 +53,10 @@ Configuration methods
 
 * check_cxx_
 
+.. _check_cxx_decl: tools/c_config.html#waflib.Tools.c_config.check_cxx_decl
+
+* check_cxx_decl_
+
 .. _check_cxx_func: tools/c_config.html#waflib.Tools.c_config.check_cxx_func
 
 * check_cxx_func_

waflib/Tools/c_config.py

@@ -732,6 +732,74 @@ def check_cc(self, *k, **kw):
 	kw['compiler'] = 'c'
 	return self.check(*k, **kw)
 
+def check_decl(symbol_name, **kw):
+	name = re.sub(r' *\(.*', '', symbol_name)
+	call = re.sub(r',', ')0, (', symbol_name.replace('(', '((').replace(')', ')0)'))
+	header = ''
+	if 'header_name' in kw:
+		header += to_header(Utils.to_list(kw['header_name'])) + '\n'
+	kw['define_name'] = 'HAVE_DECL_' + name.upper()
+	kw['fragment'] = header + \
+		'int main(int argc, char **argv) {\n' + \
+		'	(void)argc; (void)argv;\n' + \
+		'#ifndef ' + name + '\n' + \
+		'#ifdef __cplusplus\n' + \
+		'	(void)' + call + ';\n' + \
+		'#else\n' + \
+		'	(void)' + name + ';\n' + \
+		'#endif\n' + \
+		'#endif\n' + \
+		'	return 0;\n' + \
+		'}\n'
+	kw['msg'] = 'Checking whether ' + name + ' is declared'
+	return kw;
+
+@conf
+def check_cxx_decl(self, symbol_name, *k, **kw):
+	"""
+	Checks whether ``symbol_name`` is declared.  Optionally, use the
+	``header_name`` parameter to specify one or more header files providing
+	the declaration.  This check is similar to the Autoconf
+	AC_CHECK_DECLS() macro.  Compiles a test program to check whether
+	``symbol_name`` is defined as a macro or can be used as an rvalue using
+	the C++ compiler.  Optionally, you can specify function parameter types
+	to account for overloaded function declarations.   The function
+	parameter types must allow an initialization with zero (0), e.g.
+	``memcpy(void *, const void *, size_t)``.  Defines
+	``HAVE_DECL_SYMBOL_NAME`` to 1 in the configuration header if the check
+	was successful, otherwise it is not defined.  This function sets the
+	``compiler``, ``define_name``, ``features``, ``fragment``, and ``msg``
+	parameters and then calls :py:func:`waflib.Tools.c_config.check` to
+	carry out the check.
+
+	:param symbol_name: the name of the symbol to check
+	:type symbol_name: string
+	"""
+	kw = check_decl(symbol_name, **kw)
+	kw['features'] = 'cxx'
+	return self.check_cxx(*k, **kw)
+
+@conf
+def check_c_decl(self, symbol_name, *k, **kw):
+	"""
+	Checks whether ``symbol_name`` is declared.  Optionally, use the
+	``header_name`` parameter to specify one or more header files providing
+	the declaration.  This check is similar to the Autoconf
+	AC_CHECK_DECLS() macro.  Compiles a test program to check whether
+	``symbol_name`` is defined as a macro or can be used as an rvalue using
+	the C compiler.  Defines ``HAVE_DECL_SYMBOL_NAME`` to 1 in the
+	configuration header if the check was successful, otherwise it is not
+	defined.  This function sets the ``compiler``, ``define_name``,
+	``features``, ``fragment``, and ``msg`` parameters and then calls
+	:py:func:`waflib.Tools.c_config.check` to carry out the check.
+
+	:param symbol_name: the name of the symbol to check
+	:type symbol_name: string
+	"""
+	kw = check_decl(symbol_name, **kw)
+	kw['features'] = 'c'
+	return self.check_cc(*k, **kw)
+
 def check_func(function_name, **kw):
 	kw['define_name'] = 'HAVE_' + function_name.upper()
 	kw['fragment'] = CHECK_FUNC_FRAGMENT.replace('func', function_name)