RFR: JDK-8271142: package help is not displayed for missing X11/extensions/Xrandr.h

[Matthias Baesken]

Please review the following change.
On SUSE Linux 15 configure was running into this error, because of a missing X11 header :

checking for X11/extensions/Xrandr.h... no
configure: error: Could not find all X11 headers (shape.h Xrender.h Xrandr.h XTest.h Intrinsic.h).

I wondered about the missing package help output, we should display some hint what packages are missing.
In help.m4,  PKGHANDLER was detected as /usr/bin/zypper .
However only the exact string zypper is checked, this should be relaxed.
Afterwards, the package - help  was working nicely :

checking for X11/extensions/Xrandr.h... no
configure: error: Could not find all X11 headers (shape.h Xrender.h Xrandr.h XTest.h Intrinsic.h).
You might be able to fix this by running 'sudo zypper install libX11-devel libXext-devel libXrender-devel libXrandr-devel libXtst-devel libXt-devel libXi-devel'.

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Commit messages:
 - JDK-8271142

Changes: https://git.openjdk.java.net/jdk/pull/4873/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4873&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271142
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4873.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4873/head:pull/4873

PR: https://git.openjdk.java.net/jdk/pull/4873