diff --git a/src/SPC/builder/linux/LinuxBuilder.php b/src/SPC/builder/linux/LinuxBuilder.php
index 7628f667..85cda2a1 100644
--- a/src/SPC/builder/linux/LinuxBuilder.php
+++ b/src/SPC/builder/linux/LinuxBuilder.php
@@ -265,7 +265,7 @@ class LinuxBuilder extends UnixBuilderBase
             ->exec('sed -i "s|^EXTENSION_DIR = .*|EXTENSION_DIR = /' . basename(BUILD_MODULES_PATH) . '|" Makefile')
             ->exec(getenv('SPC_CMD_PREFIX_PHP_MAKE') . ' INSTALL_ROOT=' . BUILD_ROOT_PATH . " {$vars} install");
 
-        $ldflags = getenv('SPC_CMD_VAR_PHP_MAKE_EXTRA_LDFLAGS');
+        $ldflags = getenv('SPC_CMD_VAR_PHP_MAKE_EXTRA_LDFLAGS') ?: '';
         if (preg_match('/-release\s+(\S+)/', $ldflags, $matches)) {
             $release = $matches[1];
             $realLibName = 'libphp-' . $release . '.so';