RFR: 8261211: Zero: alpha builds fail with '-fstack-protector not supported for this target'

[Aleksey Shipilev]

Configuration summary:
* Name: linux-alpha-zero-slowdebug
* Debug level: slowdebug
* HS debug level: debug
* JVM variants: zero
* JVM features: zero: 'epsilongc g1gc jni-check jvmti management nmt parallelgc serialgc services vm-structs zero'
* OpenJDK target: OS: linux, CPU architecture: alpha, address length: 64
* Version string: 17-internal+0-adhoc.shade.jdk (17-internal)

Tools summary:
* Boot JDK: openjdk version "15-testing" 2020-09-15 OpenJDK Runtime Environment (build 15-testing+0-builds.shipilev.net-openjdk-jdk15-b17-20201010) OpenJDK 64-Bit Server VM (build 15-testing+0-builds.shipilev.net-openjdk-jdk15-b17-20201010, mixed mode, sharing) (at /home/shade/Install/jdk15.0.2-ea)
* Toolchain: gcc (GNU Compiler Collection)
* C Compiler: Version 9.3.0 (at /usr/bin/alpha-linux-gnu-gcc)
* C++ Compiler: Version 9.3.0 (at /usr/bin/alpha-linux-gnu-g++)

$ CONF=linux-alpha-zero-fastdebug make hotspot

* For target hotspot_variant-zero_libjvm_objs_cardTable.o:
cc1plus: error: '-fstack-protector' not supported for this target [-Werror]
cc1plus: all warnings being treated as errors

JDK-8199405 removed the conditional checks for -fstack-protector availability. I believe the intent was to trust that every recent GCC has this option. But this issue shows that stack-protector support is also arch-specific?

Linux x86_64 server configure now says:

checking if CC supports "-fstack-protector -Werror"... yes
checking if CXX supports "-fstack-protector -Werror"... yes
checking if both CC and CXX support "-fstack-protector -Werror"... yes

Linux Zero alpha configure now says:

checking if CC supports "-fstack-protector -Werror"... no
checking if CXX supports "-fstack-protector -Werror"... no
checking if both CC and CXX support "-fstack-protector -Werror"... no

Additional testing:
 - [x] Linux Zero alpha {release,fastdebug,slowdebug} cross-compilation
 - [x] Eyeballing configure logs for Linux Zero {alpha, x86_64}

-------------

Commit messages:
 - Also fix linux-zero-alpha-slowdebug
 - 8261211: Zero: alpha builds fail with '-fstack-protector not supported for this target'

Changes: https://git.openjdk.java.net/jdk/pull/2423/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2423&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261211
  Stats: 18 lines in 1 file changed: 13 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2423.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2423/head:pull/2423

PR: https://git.openjdk.java.net/jdk/pull/2423