Below are results of OpenJDK debug version building without --enable-sjavac option and with --enable-sjavac.
I build the debug version but the same results are reproduced on non debug build.

Boot JDK:
  -------------------------------------------------------------------
    $ java -version
    java version "1.7.0_07"
    Java(TM) SE Runtime Environment (build 1.7.0_07-b32)
    Java HotSpot(TM) Client VM (build 23.3-b01, mixed mode)
   ------------------------------------------------------------------

    Repository: http://hg.openjdk.java.net/jdk8/jdk8 repository.

   1) Build only debug version
           configure-arguments: --with-target-bits=32 --enable-debug

  ----- Build times -------
Start 2013-02-15 16:22:41
End 2013-02-15 16:40:01
00:00:45 corba
00:04:54 hotspot
00:00:38 jaxp
00:00:56 jaxws
00:09:18 jdk
00:00:41 langtools
00:17:20 TOTAL
-------------------------

  Build is successful.

2a) Build debug version with sjava (the same JDK in PATH, the same repository)
   configure-arguments: --with-target-bits=32 --enable-debug --enable-sjavac

100 errors
3 warnings
make[1]: *** [/cygdrive/c/Sun/OpenJDK/utils/config/jdk8-sjavac/build/windows-x86-normal-server-fastdebug/jaxws/jaxws_classes/javac_state] Error 127
make[1]: *** Waiting for unfinished jobs....
make: *** [jaxws-only] Error 2

 See the attached out.txt and out.txt files in the attached zip.

2b) Build debug version with sjava (the same JDK in PATH, the same repository)
   configure-arguments: --with-target-bits=32 --enable-debug --enable-sjavac

   with the suggested patch that checks "os.name" variable:
-----------------------------------------------------------
diff --git a/src/share/classes/com/sun/tools/sjavac/server/CompilerThread.java b/src/share/classes/com/sun/tools/sjavac/server/CompilerThread.java
--- a/src/share/classes/com/sun/tools/sjavac/server/CompilerThread.java
+++ b/src/share/classes/com/sun/tools/sjavac/server/CompilerThread.java
@@ -255,7 +255,7 @@
             }
             // Load visible sources
             Set<URI> visibleSources = new HashSet<URI>();
- boolean fix_drive_letter_case = System.getProperty("os.name").toLowerCase().equals("windows");
+ boolean fix_drive_letter_case = System.getProperty("os.name").toLowerCase().startsWith("windows");
             for (;;) {
                 String l = in.readLine();
                 if (l == null)
-----------------------------------------------------------

Compilation fails with error:
-----------------------------------------------------------
The system is out of resources.
Consult the following stack trace for details.
java.lang.OutOfMemoryError: Java heap space
-----------------------------------------------------------
 See the attached out_patch.txt and err_patch.txt files in the attached zip.