CMake: Disable fuzzshark by default.

Most people don't use fuzzshark, so don't waste compute resources
building it. OSS-Fuzz has been updated to always build fuzzshark in
https://github.com/google/oss-fuzz/pull/7373

.gitlab-ci.yml

@@ -582,7 +582,8 @@ Code Checks + Clang Warnings:
     - ./tools/check_tfs.py --commits $NUM_COMMITS | tee tfs_check.txt
     - cd build
     - printf "\e[0Ksection_start:%s:cmake_section[collapsed=true]\r\e[0KRunning CMake" "$( date +%s)"
-    - cmake -DENABLE_EXTRA_COMPILER_WARNINGS=on -DENABLE_CHECKHF_CONFLICT=on -DCMAKE_EXPORT_COMPILE_COMMANDS=on -DENABLE_CCACHE=ON -G Ninja ..
+    # We don't have an "All options" job, so build fuzzshark here.
+    - cmake -DENABLE_EXTRA_COMPILER_WARNINGS=on -DENABLE_CHECKHF_CONFLICT=on -DCMAKE_EXPORT_COMPILE_COMMANDS=on -DBUILD_fuzzshark=ON -DENABLE_CCACHE=ON -G Ninja ..
     - printf "\e[0Ksection_end:%s:cmake_section\r\e[0K" "$( date +%s)"
     - mkdir ../html
     - script --command ninja --flush --quiet --return ../tmp_clang_report.txt

CMakeOptions.txt

@@ -42,12 +42,8 @@ endif()
 option(BUILD_udpdump       "Build udpdump" ON)
 
 option(BUILD_sharkd        "Build sharkd" ON)
-if(WIN32)
-	option(BUILD_fuzzshark     "Build fuzzshark" OFF)
-else()
-	option(BUILD_fuzzshark     "Build fuzzshark" ON)
-endif()
 option(BUILD_mmdbresolve   "Build MaxMind DB resolver" ON)
+option(BUILD_fuzzshark     "Build fuzzshark" OFF)
 
 option(ENABLE_WERROR     "Treat warnings as errors" ON)
 option(ENABLE_DEBUG      "Enable debug code" ON)