fix: include foo_library header instead of suppressing lint

Addresses review feedback on #3985. The clang-tidy
misc-use-internal-linkage warning for foo_library() was triggered
because the .cc files did not include their own header, so clang-tidy
could not see the external declaration. Including the header is the
right fix and lets the NOLINTNEXTLINE suppressions be removed.

Uses the same BAZEL_BUILD vs CMake include path split already used
by every example main file that calls foo_library().

Signed-off-by: Mateen Anjum <mateenali66@gmail.com>

Author: mateenali66

examples/common/foo_library/foo_library.cc

@@ -8,6 +8,12 @@
 #include "opentelemetry/trace/tracer.h"
 #include "opentelemetry/trace/tracer_provider.h"
 
+#ifdef BAZEL_BUILD
+#  include "examples/common/foo_library/foo_library.h"
+#else
+#  include "foo_library/foo_library.h"
+#endif
+
 namespace trace = opentelemetry::trace;
 namespace nostd = opentelemetry::nostd;
 
@@ -33,7 +39,6 @@ void f2()
 }
 }  // namespace
 
-// NOLINTNEXTLINE(misc-use-internal-linkage)
 void foo_library()
 {
   auto scoped_span = trace::Scope(get_tracer()->StartSpan("library"));

examples/common/logs_foo_library/foo_library.cc

@@ -13,6 +13,12 @@
 #include "opentelemetry/trace/tracer.h"
 #include "opentelemetry/trace/tracer_provider.h"
 
+#ifdef BAZEL_BUILD
+#  include "examples/common/logs_foo_library/foo_library.h"
+#else
+#  include "logs_foo_library/foo_library.h"
+#endif
+
 namespace logs  = opentelemetry::logs;
 namespace trace = opentelemetry::trace;
 
@@ -31,7 +37,6 @@ opentelemetry::nostd::shared_ptr<logs::Logger> get_logger()
 }
 }  // namespace
 
-// NOLINTNEXTLINE(misc-use-internal-linkage)
 void foo_library()
 {
   auto span        = get_tracer()->StartSpan("span 1");