Propagate linkshared as appropriate

This follows up to our previous commit [1], which was a preparation to
address the symbol name mismatch in Mozc's TIP DLLs (google#1108) but
accidentally removed 'linkshared' from them.

While a subsequent commit [2] addressed the immediate issue by passing
'static_crt' to 'linkshared', strictly speaking they are two orthogonal
concepts. Let's decouple them to avoid future confusions.

There must be no immediate change in the final artifacts with this
commit right now.

 [1]: bc546b2
 [2]: 8d20ea6

src/build_defs.bzl

@@ -339,6 +339,7 @@ def mozc_win32_cc_prod_binary(
         deps = [],
         features = None,
         linkopts = [],
+        linkshared = False,
         cpu = CPU.X64,
         static_crt = False,
         tags = MOZC_TAGS.WIN_ONLY,
@@ -362,6 +363,7 @@ def mozc_win32_cc_prod_binary(
       deps: deps to build the executable.
       features: features to be passed to mozc_cc_binary.
       linkopts: linker options to build the executable.
+      linkshared: True if the target is a shared library (DLL).
       cpu: optional. The target CPU architecture.
       static_crt: optional. True if the target should be built with static CRT.
       tags: optional. Tags for both the library and unit test targets.
@@ -377,7 +379,7 @@ def mozc_win32_cc_prod_binary(
         deps = deps,
         features = features,
         linkopts = linkopts,
-        linkshared = static_crt,
+        linkshared = linkshared,
         tags = tags,
         target_compatible_with = target_compatible_with,
         visibility = visibility,

src/win32/custom_action/BUILD.bazel

@@ -46,6 +46,7 @@ mozc_win32_cc_prod_binary(
         "Mozc": "mozc_installer_helper.dll",
         "GoogleJapaneseInput": "GoogleIMEJaInstallerHelper.dll",
     },
+    linkshared = True,
     static_crt = True,
     tags = MOZC_TAGS.WIN_ONLY,
     target_compatible_with = ["@platforms//os:windows"],

src/win32/tip/BUILD.bazel

@@ -73,6 +73,7 @@ mozc_win32_cc_prod_binary(
         "Mozc": "mozc_tip32.dll",
         "GoogleJapaneseInput": "GoogleIMEJaTIP32.dll",
     },
+    linkshared = True,
     static_crt = True,
     tags = MOZC_TAGS.WIN_ONLY,
     target_compatible_with = ["@platforms//os:windows"],
@@ -96,6 +97,7 @@ mozc_win32_cc_prod_binary(
         "/DEBUG:FULL",
         "/PDBALTPATH:%_PDB%",
     ],
+    linkshared = True,
     static_crt = True,
     tags = MOZC_TAGS.WIN_ONLY,
     target_compatible_with = ["@platforms//os:windows"],