Add XXX_CXXFLAGS for common build

Author: crazywhalecc

src/SPC/builder/traits/UnixLibraryTrait.php

@@ -118,4 +118,13 @@ public function getLibExtraLibs(): string
     {
         return getenv($this->getSnakeCaseName() . '_LIBS') ?: '';
     }
+
+    public function getLibExtraCXXFlags(): string
+    {
+        $env = getenv($this->getSnakeCaseName() . '_CXXFLAGS') ?: '';
+        if (!str_contains($env, $this->builder->arch_cxx_flags)) {
+            $env .= $this->builder->arch_cxx_flags;
+        }
+        return $env;
+    }
 }

src/SPC/util/UnixShell.php

@@ -70,6 +70,7 @@ public function initializeEnv(BSDLibraryBase|LinuxLibraryBase|MacOSLibraryBase $
             'CFLAGS' => $library->getLibExtraCFlags(),
             'LDFLAGS' => $library->getLibExtraLdFlags(),
             'LIBS' => $library->getLibExtraLibs(),
+            'CXXFLAGS' => $library->getLibExtraCXXFlags(),
         ]);
         return $this;
     }