handle FORCE_ON, look for shared libraries only for ICU

Author: abhina-sree

llvm/cmake/config-ix.cmake

@@ -259,22 +259,31 @@ endif()
 
 #Check for icu.
 if(LLVM_ENABLE_ICU)
-  find_package(ICU COMPONENTS uc i18n)
-  if(ICU_FOUND)
-    set(HAVE_ICU 1)
+  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()
-    set(HAVE_ICU 0)
+    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)
-  find_package(Iconv)
-  if(Iconv_FOUND)
-    set(HAVE_ICONV 1)
+  if (LLVM_ENABLE_ICONV STREQUAL FORCE_ON)
+    find_package(Iconv REQUIRED)
+    if (NOT Iconv_FOUND)
+      message(FATAL_ERROR "Failed to configure iconv, but LLVM_ENABLE_ICONV is FORCE_ON")
+    endif()
   else()
-    set(HAVE_ICONV 0)
+    find_package(Iconv)
   endif()
+  set(HAVE_ICONV ${Iconv_FOUND})
 endif()
 
 # function checks