Fix aquire flex and bison when not on Windows (microsoft#4120)

* use find_program to locate flex and bison when not Windows

* reset changes to thrift/portfile.cmake

* fix aquire flex and bison on non win platforms

* [vcpkg_find_acquire_program] Indentation and use CMAKE_HOST_WIN32

scripts/cmake/vcpkg_find_acquire_program.cmake

@@ -134,17 +134,29 @@ function(vcpkg_find_acquire_program VAR)
     set(ARCHIVE "meson-0.43.0.zip")
     set(HASH dde4de72eff37046731224f32aa5f4618d45bdf148cec2d1af6e25e7522ebc2b04aedc9eceed483dfa93823a0ea7ea472d0c0c9380061bf3ee2f16b87dd1425e)
   elseif(VAR MATCHES "FLEX")
+  if(CMAKE_HOST_WIN32)
     set(PROGNAME win_flex)
-    set(PATHS ${DOWNLOADS}/tools/win_flex)
-    set(URL "https://sourceforge.net/projects/winflexbison/files/win_flex_bison-2.5.9.zip/download")
-    set(ARCHIVE "win_flex_bison-2.5.9.zip")
-    set(HASH 9580f0e46893670a011645947c1becda69909a41a38bb4197fe33bd1ab7719da6b80e1be316f269e1a4759286870d49a9b07ef83afc4bac33232bd348e0bc814)
+      set(PATHS ${DOWNLOADS}/tools/win_flex)
+      set(URL "https://sourceforge.net/projects/winflexbison/files/win_flex_bison-2.5.9.zip/download")
+      set(ARCHIVE "win_flex_bison-2.5.9.zip")
+      set(HASH 9580f0e46893670a011645947c1becda69909a41a38bb4197fe33bd1ab7719da6b80e1be316f269e1a4759286870d49a9b07ef83afc4bac33232bd348e0bc814)
+    else()
+      set(PROGNAME flex)
+      set(APT_PACKAGE_NAME flex)
+      set(BREW_PACKAGE_NAME flex)
+    endif()
   elseif(VAR MATCHES "BISON")
-    set(PROGNAME win_bison)
-    set(PATHS ${DOWNLOADS}/tools/win_bison)
-    set(URL "https://sourceforge.net/projects/winflexbison/files/win_flex_bison-2.5.9.zip/download")
-    set(ARCHIVE "win_flex_bison-2.5.9.zip")
-    set(HASH 9580f0e46893670a011645947c1becda69909a41a38bb4197fe33bd1ab7719da6b80e1be316f269e1a4759286870d49a9b07ef83afc4bac33232bd348e0bc814)
+    if(CMAKE_HOST_WIN32)
+      set(PROGNAME win_bison)
+      set(PATHS ${DOWNLOADS}/tools/win_bison)
+      set(URL "https://sourceforge.net/projects/winflexbison/files/win_flex_bison-2.5.9.zip/download")
+      set(ARCHIVE "win_flex_bison-2.5.9.zip")
+      set(HASH 9580f0e46893670a011645947c1becda69909a41a38bb4197fe33bd1ab7719da6b80e1be316f269e1a4759286870d49a9b07ef83afc4bac33232bd348e0bc814)
+    else()
+      set(PROGNAME bison)
+      set(APT_PACKAGE_NAME bison)
+      set(BREW_PACKAGE_NAME bison)
+    endif()
   elseif(VAR MATCHES "GPERF")
     set(PROGNAME gperf)
     set(PATHS ${DOWNLOADS}/tools/gperf/bin)