[llvm][cmake] Remove version number from runtimes in PROJECTS warnings (#152457)

Judging from the reaction to
llvm/llvm-project#152302, we are not ready to
make this a fatal error.

Remove the specific version number, and update the libc message to match
the others' wording.

Author: DavidSpickett

llvm/CMakeLists.txt

@@ -187,28 +187,29 @@ if ("lldb" IN_LIST LLVM_ENABLE_PROJECTS)
 endif ()
 
 if ("libc" IN_LIST LLVM_ENABLE_PROJECTS)
-  message(WARNING "Using LLVM_ENABLE_PROJECTS=libc is deprecated.  Please use "
+  message(WARNING "Using LLVM_ENABLE_PROJECTS=libc is deprecated now, and will "
+    "become a fatal error in a future release. Please use "
     "-DLLVM_ENABLE_RUNTIMES=libc or see the instructions at "
     "https://libc.llvm.org/ for building the runtimes.")
 endif()
 
 if ("compiler-rt" IN_LIST LLVM_ENABLE_PROJECTS)
   message(WARNING "Using LLVM_ENABLE_PROJECTS=compiler-rt is deprecated now, and will "
-    "become a fatal error in the LLVM 21 release.  Please use "
+    "become a fatal error in a future release.  Please use "
     "-DLLVM_ENABLE_RUNTIMES=compiler-rt or see the instructions at "
     "https://compiler-rt.llvm.org/ for building the runtimes.")
 endif()
 
 if ("offload" IN_LIST LLVM_ENABLE_PROJECTS)
   message(WARNING "Using LLVM_ENABLE_PROJECTS=offload is deprecated now, and will "
-    "become a fatal error in the LLVM 21 release.  Please use "
+    "become a fatal error in a future release.  Please use "
     "-DLLVM_ENABLE_RUNTIMES=offload or see the instructions at "
     "https://openmp.llvm.org/ for building the runtimes.")
 endif()
 
 if ("openmp" IN_LIST LLVM_ENABLE_PROJECTS)
   message(WARNING "Using LLVM_ENABLE_PROJECTS=openmp is deprecated now, and will "
-    "become a fatal error in the LLVM 21 release.  Please use "
+    "become a fatal error in a future release.  Please use "
     "-DLLVM_ENABLE_RUNTIMES=openmp or see the instructions at "
     "https://openmp.llvm.org/ for building the runtimes.")
 endif()
@@ -221,7 +222,7 @@ endif ()
 
 if ("libclc" IN_LIST LLVM_ENABLE_PROJECTS)
   message(WARNING "Using LLVM_ENABLE_PROJECTS=libclc is deprecated now, and will "
-    "become a fatal error in the LLVM 21 release.  Please use "
+    "become a fatal error in a future release.  Please use "
     "-DLLVM_ENABLE_RUNTIMES=libclc or see the instructions at "
     "https://libclc.llvm.org/ for building the runtimes.")
 endif()