ORC-1751: [C++] fix syntax error in ThirdpartyToolchain

### What changes were proposed in this pull request?
fix syntax error in ThirdpartyToolchain

### Why are the changes needed?
Handle the issue discussed [here]( apache/arrow#43417)

### How was this patch tested?
Test it locally

### Was this patch authored or co-authored using generative AI tooling?
NO

Closes #1997 from luffy-zh/branch-2.0.

Authored-by: luffy-zh <zhnice@outlook.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

cmake_modules/ThirdpartyToolchain.cmake

@@ -111,7 +111,7 @@ add_library (orc_snappy INTERFACE)
 add_library (orc::snappy ALIAS orc_snappy)
 if (ORC_PACKAGE_KIND STREQUAL "conan")
   target_link_libraries(orc_snappy INTERFACE ${Snappy_LIBRARIES})
-elseif (ORC_PREFER_STATIC_SNAPPY AND ${SNAPPY_STATIC_LIB})
+elseif (ORC_PREFER_STATIC_SNAPPY AND SNAPPY_STATIC_LIB)
   target_link_libraries(orc_snappy INTERFACE ${SNAPPY_STATIC_LIB})
 else ()
   target_link_libraries(orc_snappy INTERFACE ${SNAPPY_LIBRARY})
@@ -169,7 +169,7 @@ add_library (orc_zlib INTERFACE)
 add_library (orc::zlib ALIAS orc_zlib)
 if (ORC_PACKAGE_KIND STREQUAL "conan")
   target_link_libraries (orc_zlib INTERFACE ${ZLIB_LIBRARIES})
-elseif (ORC_PREFER_STATIC_ZLIB AND ${ZLIB_STATIC_LIB})
+elseif (ORC_PREFER_STATIC_ZLIB AND ZLIB_STATIC_LIB)
   target_link_libraries (orc_zlib INTERFACE ${ZLIB_STATIC_LIB})
 else ()
   target_link_libraries (orc_zlib INTERFACE ${ZLIB_LIBRARY})
@@ -230,7 +230,7 @@ add_library (orc_zstd INTERFACE)
 add_library (orc::zstd ALIAS orc_zstd)
 if (ORC_PACKAGE_KIND STREQUAL "conan")
   target_link_libraries (orc_zstd INTERFACE ${zstd_LIBRARIES})
-elseif (ORC_PREFER_STATIC_ZSTD AND ${ZSTD_STATIC_LIB})
+elseif (ORC_PREFER_STATIC_ZSTD AND ZSTD_STATIC_LIB)
   target_link_libraries (orc_zstd INTERFACE ${ZSTD_STATIC_LIB})
 else ()
   target_link_libraries (orc_zstd INTERFACE ${ZSTD_LIBRARY})
@@ -288,7 +288,7 @@ add_library (orc_lz4 INTERFACE)
 add_library (orc::lz4 ALIAS orc_lz4)
 if (ORC_PACKAGE_KIND STREQUAL "conan")
   target_link_libraries (orc_lz4 INTERFACE ${lz4_LIBRARIES})
-elseif (ORC_PREFER_STATIC_LZ4 AND ${LZ4_STATIC_LIB})
+elseif (ORC_PREFER_STATIC_LZ4 AND LZ4_STATIC_LIB)
   target_link_libraries (orc_lz4 INTERFACE ${LZ4_STATIC_LIB})
 else ()
   target_link_libraries (orc_lz4 INTERFACE ${LZ4_LIBRARY})
@@ -389,7 +389,7 @@ if (BUILD_CPP_TESTS)
   add_library (orc::gmock ALIAS orc_gmock)
   add_library (orc_gtest INTERFACE)
   add_library (orc::gtest ALIAS orc_gtest)
-  if (ORC_PREFER_STATIC_GMOCK AND ${GMOCK_STATIC_LIB})
+  if (ORC_PREFER_STATIC_GMOCK AND GMOCK_STATIC_LIB)
     target_link_libraries (orc_gmock INTERFACE ${GMOCK_STATIC_LIB})
     target_link_libraries (orc_gtest INTERFACE ${GTEST_STATIC_LIB})
   else ()
@@ -464,7 +464,7 @@ add_library (orc::protoc ALIAS orc_protoc)
 
 if (ORC_PACKAGE_KIND STREQUAL "conan")
   target_link_libraries (orc_protobuf INTERFACE ${protobuf_LIBRARIES})
-elseif (ORC_PREFER_STATIC_PROTOBUF AND ${PROTOBUF_STATIC_LIB})
+elseif (ORC_PREFER_STATIC_PROTOBUF AND PROTOBUF_STATIC_LIB)
   target_link_libraries (orc_protobuf INTERFACE ${PROTOBUF_STATIC_LIB})
 else ()
   target_link_libraries (orc_protobuf INTERFACE ${PROTOBUF_LIBRARY})
@@ -476,7 +476,7 @@ else ()
 endif ()
 
 if (NOT ORC_PACKAGE_KIND STREQUAL "conan")
-  if (ORC_PREFER_STATIC_PROTOBUF AND ${PROTOC_STATIC_LIB})
+  if (ORC_PREFER_STATIC_PROTOBUF AND PROTOC_STATIC_LIB)
     target_link_libraries (orc_protoc INTERFACE ${PROTOC_STATIC_LIB})
   else ()
     target_link_libraries (orc_protoc INTERFACE ${PROTOC_LIBRARY})