Zephir\Compiler::generatePackageDependenciesM4 PHP Method

    public function generatePackageDependenciesM4($contentM4)
    {
        $packageDependencies = $this->config->get('package-dependencies');
        if (is_array($packageDependencies)) {
            $pkgconfigM4 = $this->backend->getTemplateFileContents('pkg-config.m4');
            $pkgconfigCheckM4 = $this->backend->getTemplateFileContents('pkg-config-check.m4');
            $extraCFlags = '';
            foreach ($packageDependencies as $pkg => $version) {
                $pkgM4Buf = $pkgconfigCheckM4;
                $operator = '=';
                $operatorCmd = '--exact-version';
                $ar = explode("=", $version);
                if (count($ar) == 1) {
                    if ($version == '*') {
                        $version = '0.0.0';
                        $operator = '>=';
                        $operatorCmd = '--atleast-version';
                    }
                } else {
                    switch ($ar[0]) {
                        case '<':
                            $operator = '<=';
                            $operatorCmd = '--max-version';
                            $version = trim($ar[1]);
                            break;
                        case '>':
                            $operator = '>=';
                            $operatorCmd = '--atleast-version';
                            $version = trim($ar[1]);
                            break;
                        default:
                            $version = trim($ar[1]);
                            break;
                    }
                }
                $toReplace = array('%PACKAGE_LOWER%' => strtolower($pkg), '%PACKAGE_UPPER%' => strtoupper($pkg), '%PACKAGE_REQUESTED_VERSION%' => $operator . ' ' . $version, '%PACKAGE_PKG_CONFIG_COMPARE_VERSION%' => $operatorCmd . '=' . $version);
                foreach ($toReplace as $mark => $replace) {
                    $pkgM4Buf = str_replace($mark, $replace, $pkgM4Buf);
                }
                $pkgconfigM4 .= $pkgM4Buf;
                $extraCFlags .= '$PHP_' . strtoupper($pkg) . '_INCS ';
            }
            $contentM4 = str_replace('%PROJECT_EXTRA_CFLAGS%', '%PROJECT_EXTRA_CFLAGS% ' . $extraCFlags, $contentM4);
            $contentM4 = str_replace('%PROJECT_PACKAGE_DEPENDENCIES%', $pkgconfigM4, $contentM4);
            return $contentM4;
        }
        $contentM4 = str_replace('%PROJECT_PACKAGE_DEPENDENCIES%', '', $contentM4);
        return $contentM4;
    }