I got an intermittent build problem building jdk9/hs-rt:

Note: Recompile with -Xlint:unchecked for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 151: error: syntax error before or at: throwOutOfMemoryError
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 151: error: syntax error before or at: *
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 151: error: undefined or missing type for: const (E_UNDEFINED_OR_MISSING_TYPE)
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: undefined symbol: env
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: cannot dereference non-pointer type
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: undefined struct/union member: ThrowNew
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: left operand of "->" must be pointer to struct/union
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: cannot dereference non-pointer type
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: undefined struct/union member: FindClass
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: left operand of "->" must be pointer to struct/union
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: function designator is not of function type
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 154: error: undefined symbol: cause
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 153: error: function designator is not of function type
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 157: error: syntax error before or at: throwInterruptedIOException
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 157: error: syntax error before or at: *
"/opt/jprt/T/P1/174218.mikael/s/jdk/src/demo/solaris/jni/Poller/Poller.c", line 157: error: undefined or missing type for: const (E_UNDEFINED_OR_MISSING_TYPE)

If I didn't know better I'd say it looks like the generated Poller.h file (generated from Poller.java) wasn't generated correctly - maybe it ended up empty or hadn't yet been fully generated?