Fix build with external LLVM28.

It declares those 2 initialize functions as C linkage, so make sure we match it
(in our version they are not declared at all).

libclamav/c++/bytecode2llvm.cpp

@@ -67,8 +67,10 @@
 #include "llvm/Support/Timer.h"
 #include "llvm/System/Threading.h"
 
+extern "C" {
 void LLVMInitializeX86AsmPrinter();
 void LLVMInitializePowerPCAsmPrinter();
+}
 #include "llvm/Target/TargetSelect.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetOptions.h"
@@ -133,7 +135,10 @@ struct cli_bcengine {
 extern "C" uint8_t cli_debug_flag;
 namespace {
 
+#ifndef LLVM28
 #define LLVM28
+#endif
+
 #ifdef LLVM28
 #define llvm_report_error(x) report_fatal_error(x)
 #define llvm_install_error_handler(x) install_fatal_error_handler(x)
@@ -214,7 +219,7 @@ void do_shutdown() {
 
 static void NORETURN jit_exception_handler(void)
 {
-    jmp_buf* buf = (jmp_buf*)ExceptionReturn.get();
+    jmp_buf* buf = const_cast<jmp_buf*>(ExceptionReturn.get());
     if (buf) {
 	// For errors raised during bytecode generation and execution.
 	longjmp(*buf, 1);
@@ -224,7 +229,7 @@ static void NORETURN jit_exception_handler(void)
 	cli_errmsg("[Bytecode JIT]: exception handler called, but no recovery point set up");
 	// should never happen, we remove the error handler when we don't use
 	// LLVM anymore, and when we use it, we do set an error recovery point.
-	assert(0 && "[Bytecode JIT]: no exception handler recovery installed, but exception hit!");
+	llvm_unreachable("Bytecode JIT]: no exception handler recovery installed, but exception hit!");
     }
 }
 
@@ -2281,9 +2286,9 @@ void cli_bytecode_debug_printsrc(const struct cli_bc_ctx *ctx)
     }
     assert(ctx->line < lines->linev.size());
 
+#ifndef LLVM28
     int line = (int)ctx->line ? (int)ctx->line : -1;
     int col = (int)ctx->col ? (int)ctx->col : -1;
-#ifndef LLVM28
     //TODO: print this ourselves, instead of using SMDiagnostic
     SMDiagnostic diag(ctx->file, line, col,
 		 "", std::string(lines->linev[ctx->line-1], lines->linev[ctx->line]-1));