diff --git a/config/lib.json b/config/lib.json
index 63a3c8d6..491aea1f 100644
--- a/config/lib.json
+++ b/config/lib.json
@@ -470,6 +470,11 @@
         "static-libs-unix": [
             "libiconv.a",
             "libcharset.a"
+        ],
+        "headers": [
+            "iconv.h",
+            "libcharset.h",
+            "localcharset.h"
         ]
     },
     "libiconv-win": {
@@ -860,10 +865,17 @@
         "pkg-configs": [
             "openssl"
         ],
+        "static-libs-unix": [
+            "libssl.a",
+            "libcrypto.a"
+        ],
         "static-libs-windows": [
             "libssl.lib",
             "libcrypto.lib"
         ],
+        "headers": [
+            "openssl"
+        ],
         "lib-depends": [
             "zlib"
         ]
@@ -970,6 +982,11 @@
             "odbccr",
             "odbcinst"
         ],
+        "static-libs-unix": [
+            "libodbc.a",
+            "libodbccr.a",
+            "libodbcinst.a"
+        ],
         "lib-depends": [
             "libiconv"
         ]
@@ -1014,6 +1031,10 @@
         ],
         "static-libs-windows": [
             "zlib_a.lib"
+        ],
+        "headers": [
+            "zlib.h",
+            "zconf.h"
         ]
     },
     "zstd": {
@@ -1021,10 +1042,18 @@
         "pkg-configs": [
             "libzstd"
         ],
+        "static-libs-unix": [
+            "libzstd.a"
+        ],
         "static-libs-windows": [
             "zstd.lib",
             "zstd_static.lib"
         ],
+        "headers-unix": [
+            "zdict.h",
+            "zstd.h",
+            "zstd_errors.h"
+        ],
         "headers-windows": [
             "zstd.h",
             "zstd_errors.h"
diff --git a/src/SPC/builder/LibraryBase.php b/src/SPC/builder/LibraryBase.php
index 701aeedb..3e97a4f8 100644
--- a/src/SPC/builder/LibraryBase.php
+++ b/src/SPC/builder/LibraryBase.php
@@ -154,7 +154,8 @@ abstract class LibraryBase
                 FileSystem::extractPackage($install_file, $lock['source_type'], DOWNLOAD_PATH . '/' . $install_file, BUILD_ROOT_PATH);
                 $this->install();
                 return LIB_STATUS_OK;
-            } catch (SPCException $e) {
+            }
+            catch (SPCException $e) {
                 logger()->error('Failed to extract pre-built library [' . static::NAME . ']: ' . $e->getMessage());
                 return LIB_STATUS_INSTALL_FAILED;
             }
@@ -365,6 +366,25 @@ abstract class LibraryBase
 
     protected function isLibraryInstalled(): bool
     {
+        $pkg_configs = Config::getLib(static::NAME, 'pkg-configs', []);
+        if (count($pkg_configs) !== 0) {
+            $pkg_config_path = getenv('PKG_CONFIG_PATH') ?: '';
+            $search_paths = array_unique(array_filter(explode(is_unix() ? ':' : ';', $pkg_config_path)));
+
+            foreach ($pkg_configs as $name) {
+                $found = false;
+                foreach ($search_paths as $path) {
+                    if (file_exists($path . "/{$name}.pc")) {
+                        $found = true;
+                        break;
+                    }
+                }
+                if (!$found) {
+                    return false;
+                }
+            }
+            return true; // allow using system dependencies if pkg_config_path is explicitly defined
+        }
         foreach (Config::getLib(static::NAME, 'static-libs', []) as $name) {
             if (!file_exists(BUILD_LIB_PATH . "/{$name}")) {
                 return false;
@@ -375,20 +395,6 @@ abstract class LibraryBase
                 return false;
             }
         }
-        $pkg_config_path = getenv('PKG_CONFIG_PATH') ?: '';
-        $search_paths = array_unique(array_filter(explode(is_unix() ? ':' : ';', $pkg_config_path)));
-        foreach (Config::getLib(static::NAME, 'pkg-configs', []) as $name) {
-            $found = false;
-            foreach ($search_paths as $path) {
-                if (file_exists($path . "/{$name}.pc")) {
-                    $found = true;
-                    break;
-                }
-            }
-            if (!$found) {
-                return false;
-            }
-        }
         foreach (Config::getLib(static::NAME, 'bin', []) as $name) {
             if (!file_exists(BUILD_BIN_PATH . "/{$name}")) {
                 return false;