consider e.g. jdk.compiler. modules.xml includes this information about it:
  <module>
    <name>jdk.compiler</name>
    <depend>java.base</depend>
    <depend re-exports="true">java.compiler</depend>
[snip - exports]
So, it could be expected that:
make jdk.compiler
is equivalent to:
make java.base java.compiler jdk.compiler

But, it is not:
---
$ make clean >/dev/null 2>&1; make jdk.compiler >/dev/null 2>&1; build/linux-x86_64-normal-server-release/jdk/bin/javah
Error: could not open `/usr/local/home/lahvac/src/jdk/tl.precommit/build/linux-x86_64-normal-server-release/jdk/lib/amd64/jvm.cfg'
$ make java.base java.compiler jdk.compiler >/dev/null 2>&1; build/linux-x86_64-normal-server-release/jdk/bin/javah
Usage:
  javah [options] <classes>
where [options] include:
  -o <file> Output file (only one of -d or -o may be used)
  -d <dir> Output directory
  -v -verbose Enable verbose output
  -h --help -? Print this message
  -version Print version information
  -jni Generate JNI-style header file (default)
  -force Always write output files
  -classpath <path> Path from which to load classes
  -cp <path> Path from which to load classes
  -bootclasspath <path> Path from which to load bootstrap classes
<classes> are specified with their fully qualified names
(for example, java.lang.Object).