Don't harcode -ldl test/sanitizer_common/TestCases

[krytarowski]

Summary

The dl library does not exist on all system and in particular
this breaks build on NetBSD. Make it conditional and
enable only for Linux, following the approach from other
test suites in the same repository.

compiler-rt/trunk/test/sanitizer_common/TestCases/get_module_and_offset_for_pc.cc

 // RUN: mkdir -p %t-dir
 // RUN: %clangxx -DSHARED %s -shared -o %t-dir/get_module_and_offset_for_pc.so -fPIC
-// RUN: %clangxx -DSO_DIR=\"%t-dir\" -O0 %s -ldl -o %t
+// RUN: %clangxx -DSO_DIR=\"%t-dir\" -O0 %s -o %t
 // RUN: %run %t 2>&1 | FileCheck %s
 
 // UNSUPPORTED: i386-darwin
 // XFAIL: android
 
 // Tests __sanitizer_get_module_and_offset_for_pc.
 
 #include <assert.h>

compiler-rt/trunk/test/sanitizer_common/TestCases/sanitizer_coverage_symbolize.cc

 // Tests trace pc guard coverage collection.
 //
 // REQUIRES: x86_64-linux
 // XFAIL: tsan
 //
 // RUN: DIR=%t_workdir
 // RUN: rm -rf $DIR
 // RUN: mkdir -p $DIR
 // RUN: cd $DIR
-// RUN: %clangxx -O0 -fsanitize-coverage=trace-pc-guard %s -ldl -o %t
+// RUN: %clangxx -O0 -fsanitize-coverage=trace-pc-guard %s -o %t
 // RUN: %env_tool_opts=coverage=1 %t 2>&1 | FileCheck %s
 // RUN: rm -rf $DIR
 
 #include <stdio.h>
 
 int foo() {
   fprintf(stderr, "foo\n");
   return 1;

compiler-rt/trunk/test/sanitizer_common/TestCases/sanitizer_coverage_trace_pc_guard.cc

 // Tests trace pc guard coverage collection.
 
 // REQUIRES: has_sancovcc,stable-runtime
 // UNSUPPORTED: ubsan,i386-darwin
 // XFAIL: tsan,powerpc64,s390x,mips
 // XFAIL: android && asan
 
 // RUN: DIR=%t_workdir
 // RUN: rm -rf $DIR
 // RUN: mkdir -p $DIR
 // RUN: cd $DIR
-// RUN: %clangxx -O0 -fsanitize-coverage=trace-pc-guard %s -ldl -o %t
+// RUN: %clangxx -O0 -fsanitize-coverage=trace-pc-guard %s -o %t
 // RUN: %env_tool_opts=coverage=1 %t 2>&1 | FileCheck %s
 // RUN: %sancovcc  -covered-functions -strip_path_prefix=TestCases/ *.sancov %t 2>&1 | \
 // RUN:   FileCheck --check-prefix=CHECK-SANCOV %s
 // RUN: %env_tool_opts=coverage=0 %t 2>&1 | FileCheck --check-prefix=CHECK-NOCOV %s
 // RUN: rm -rf $DIR
 // Make some room to stabilize line numbers
 
 #include <stdio.h>

compiler-rt/trunk/test/sanitizer_common/lit.common.cfg

elif config.android:
   # which does not work for abort()-terminated programs.
   default_tool_options += ['abort_on_error=0']
 
 default_tool_options_str = ':'.join(default_tool_options)
 if default_tool_options_str:
   config.environment[tool_options] = default_tool_options_str
   default_tool_options_str += ':'
 
+if config.host_os in ['Linux']:
+  extra_link_flags = ["-ldl"]
+else:
+  extra_link_flags = []
+
 clang_cflags = config.debug_info_flags + tool_cflags + [config.target_cflags]
+clang_cflags += extra_link_flags
 clang_cxxflags = config.cxx_mode_flags + clang_cflags
 
 def build_invocation(compile_flags):
   return " " + " ".join([config.clang] + compile_flags) + " "
 
 config.substitutions.append( ("%clang ", build_invocation(clang_cflags)) )
 config.substitutions.append( ("%clangxx ", build_invocation(clang_cxxflags)) )
 config.substitutions.append( ("%collect_stack_traces", collect_stack_traces) )