build: fix C string encoding for PRODUCT_DIR_ABS

Since the `PRODUCT_DIR_ABS` gyp variable is meant to be used
in a C string in the OpenSSL config, provide a version of it
that actually provides it in a way that is always usable as a
C string. Otherwise, unescaped characters in the path can mess
with the string definitions; for example, building in paths
on Windows whose directories start with valid or invalid escape
sequences (e.g.: `C:\...\x61foobar\...` or `C:\...\456789\...`)
can result in failing builds or incorrect paths provided to
OpenSSL.

PR-URL: #56111
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: addaleax

deps/openssl/openssl.gyp

@@ -5,19 +5,13 @@
     'nasm_version%': '0.0',
     'openssl-cli': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)openssl-cli<(EXECUTABLE_SUFFIX)',
     'conditions': [
-      ['OS == "win"', {
-        'obj_dir_abs': '<(PRODUCT_DIR_ABS)/obj',
-      }],
       ['GENERATOR == "ninja"', {
-        'obj_dir_abs': '<(PRODUCT_DIR_ABS)/obj',
-        'modules_dir': '<(PRODUCT_DIR_ABS)/obj/lib/openssl-modules',
+        'modules_dir': '<(PRODUCT_DIR_ABS_CSTR)/obj/lib/openssl-modules',
       }, {
-        'obj_dir_abs%': '<(PRODUCT_DIR_ABS)/obj.target',
-        'modules_dir': '<(PRODUCT_DIR_ABS)/obj.target/deps/openssl/lib/openssl-modules',
+        'modules_dir': '<(PRODUCT_DIR_ABS_CSTR)/obj.target/deps/openssl/lib/openssl-modules',
       }],
       ['OS=="mac"', {
-        'obj_dir_abs%': '<(PRODUCT_DIR_ABS)/obj.target',
-        'modules_dir': '<(PRODUCT_DIR_ABS)/obj.target/deps/openssl/lib/openssl-modules',
+        'modules_dir': '<(PRODUCT_DIR_ABS_CSTR)/obj.target/deps/openssl/lib/openssl-modules',
       }],
     ],
   },