[llvm] Create a CharSetConverter class with both iconv and icu support (PR #74516)

[Abhina Sree via llvm-commits]

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@@ -257,6 +257,35 @@ else()
   set(LLVM_ENABLE_TERMINFO 0)
 endif()
 
+#Check for icu.
+if(LLVM_ENABLE_ICU)
+  set(LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  set(CMAKE_FIND_LIBRARY_SUFFIXES ".so")
+  if (LLVM_ENABLE_ICU STREQUAL FORCE_ON)
+    find_package(ICU REQUIRED COMPONENTS uc i18n)
+    if (NOT ICU_FOUND)
+      message(FATAL_ERROR "Failed to configure icu, but LLVM_ENABLE_ICU is FORCE_ON")
+    endif()
+  else()
+    find_package(ICU COMPONENTS uc i18n)
+  endif()
+  set(HAVE_ICU ${ICU_FOUND})
+  set(CMAKE_FIND_LIBRARY_SUFFIXES ${LIBRARY_SUFFIXES})
+endif()
+
+# Check for iconv.
+if(LLVM_ENABLE_ICONV)
+  if (LLVM_ENABLE_ICONV STREQUAL FORCE_ON)
+    find_package(Iconv REQUIRED)
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abhina-sree wrote:

I modified it now to only accept builtin iconv, so this should address the concern about accidentally picking up GNU iconv. Please let me know if this solves the Windows issue, thanks!

https://github.com/llvm/llvm-project/pull/74516