Consider Require-Capability when validating BREE

Presence of osgi.ee capability ‘Require-Capability’ should mitigate
absence of BREE headers in the manifest. The current parser has no
awareness of Require-Capability header. In future the parser should
consider this header too while evaluating BREE header.
Fixes: eclipse-pde#140

ui/org.eclipse.pde.core/src/org/eclipse/pde/internal/core/builders/BundleErrorReporter.java

@@ -587,7 +587,8 @@ private void validateRequiredExecutionEnvironment() {
  IPath currentPath = entry.getPath();
  if (JavaRuntime.newDefaultJREContainerPath().matchingFirstSegments(currentPath) > 0) {
  String eeId = JavaRuntime.getExecutionEnvironmentId(currentPath);
- if (eeId != null) {
+ IHeader header = getHeader(Constants.REQUIRE_CAPABILITY);
+ if (eeId != null && header == null) {
  VirtualMarker marker = report(PDECoreMessages.BundleErrorReporter_noExecutionEnvironmentSet, 1, sev, PDEMarkerFactory.M_EXECUTION_ENVIRONMENT_NOT_SET, PDEMarkerFactory.CAT_EE);
  addMarkerAttribute(marker, "ee_id", eeId); //$NON-NLS-1$
  addMarkerAttribute(marker,PDEMarkerFactory.compilerKey, CompilerFlags.P_INCOMPATIBLE_ENV);
@@ -615,7 +616,8 @@ private void validateRequiredExecutionEnvironment() {
  if (vm != null) {
  for (IExecutionEnvironment systemEnv : systemEnvs) {
  // Get strictly compatible EE for the default VM
- if (systemEnv.isStrictlyCompatible(vm)) {
+ IHeader header = getHeader(Constants.REQUIRE_CAPABILITY);
+ if (systemEnv.isStrictlyCompatible(vm) && header == null) {
  VirtualMarker marker = report(PDECoreMessages.BundleErrorReporter_noExecutionEnvironmentSet, 1, sev, PDEMarkerFactory.M_EXECUTION_ENVIRONMENT_NOT_SET, PDEMarkerFactory.CAT_EE);
  addMarkerAttribute(marker, "ee_id", systemEnv.getId()); //$NON-NLS-1$
  addMarkerAttribute(marker,PDEMarkerFactory.compilerKey, CompilerFlags.P_INCOMPATIBLE_ENV);