Ubuntu 21.04 build failed

I follow README.md to build JetBrainRuntime.

but it failed and i couldn't figure it out.

my os: Ubuntu 21.04

Thanks in advance.

output below:

````
Building target 'images' in configuration 'linux-x86_64-normal-server-slowdebug'
Compiling 8 files for BUILD_TOOLS_LANGTOOLS
警告: [path] 错误的路径元素 "$JAVA_HOME/lib": 没有这种文件或目录
警告: [path] 错误的路径元素 "$JAVA_HOME/jre/lib": 没有这种文件或目录
错误: 发现警告, 但指定了 -Werror
Creating support/modules_libs/java.base/server/libjvm.so from 923 file(s)
1 个错误
2 个警告
Creating hotspot/variant-server/libjvm/gtest/libjvm.so from 108 file(s)
Creating hotspot/variant-server/libjvm/gtest/gtestLauncher from 1 file(s)
gmake[3]: *** [ToolsLangtools.gmk:40：/home/teaho/Env/JetBrainsRuntime/build/linux-x86_64-normal-server-slowdebug/buildtools/langtools_tools_classes/_the.BUILD_TOOLS_LANGTOOLS_batch] 错误 1
gmake[2]: *** [make/Main.gmk:73：buildtools-langtools] 错误 2
gmake[2]: *** 正在等待未完成的任务....
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp: In static member function ‘static void os::Linux::print_process_memory_info(outputStream*)’:
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:2333:26: error: ‘mallinfo mallinfo()’ is deprecated [-Werror=deprecated-declarations]
2333 | struct mallinfo mi = ::mallinfo();
| ^~~~~~~~
In file included from /home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:112:
/usr/include/malloc.h:118:24: note: declared here
118 | extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
| ^~~~~~~~
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:2333:35: error: ‘mallinfo mallinfo()’ is deprecated [-Werror=deprecated-declarations]
2333 | struct mallinfo mi = ::mallinfo();
| ^
In file included from /home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:112:
/usr/include/malloc.h:118:24: note: declared here
118 | extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
| ^~~~~~~~
cc1plus: all warnings being treated as errors
gmake[3]: *** [lib/CompileJvm.gmk:153：/home/teaho/Env/JetBrainsRuntime/build/linux-x86_64-normal-server-slowdebug/hotspot/variant-server/libjvm/objs/os_linux.o] 错误 1
gmake[3]: *** 正在等待未完成的任务....
gmake[2]: *** [make/Main.gmk:272：hotspot-server-libs] 错误 2

ERROR: Build failed for target 'images' in configuration 'linux-x86_64-normal-server-slowdebug' (exit code 2)

=== Output from failing command(s) repeated here ===
* For target buildtools_langtools_tools_classes__the.BUILD_TOOLS_LANGTOOLS_batch:
警告: [path] 错误的路径元素 "$JAVA_HOME/lib": 没有这种文件或目录
警告: [path] 错误的路径元素 "$JAVA_HOME/jre/lib": 没有这种文件或目录
错误: 发现警告, 但指定了 -Werror
1 个错误
2 个警告
* For target hotspot_variant-server_libjvm_objs_os_linux.o:
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp: In static member function ‘static void os::Linux::print_process_memory_info(outputStream*)’:
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:2333:26: error: ‘mallinfo mallinfo()’ is deprecated [-Werror=deprecated-declarations]
2333 | struct mallinfo mi = ::mallinfo();
| ^~~~~~~~
In file included from /home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:112:
/usr/include/malloc.h:118:24: note: declared here
118 | extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
| ^~~~~~~~
/home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:2333:35: error: ‘mallinfo mallinfo()’ is deprecated [-Werror=deprecated-declarations]
2333 | struct mallinfo mi = ::mallinfo();
| ^
In file included from /home/teaho/Env/JetBrainsRuntime/src/hotspot/os/linux/os_linux.cpp:112:
/usr/include/malloc.h:118:24: note: declared here
118 | extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
| ^~~~~~~~
... (rest of output omitted)

* All command lines available in /home/teaho/Env/JetBrainsRuntime/build/linux-x86_64-normal-server-slowdebug/make-support/failure-logs.
=== End of repeated output ===

No indication of failed target found.
Hint: Try searching the build log for '] Error'.
Hint: See doc/building.html#troubleshooting for assistance.

make[1]: *** [/home/teaho/Env/JetBrainsRuntime/make/Init.gmk:305：main] 错误 2
make: *** [/home/teaho/Env/JetBrainsRuntime/make/Init.gmk:186：images] 错误 2

````

Start with README.md and doc/building.html, then inspect the failure logs under build/linux-x86_64-normal-server-slowdebug/make-support. Reproduce the images target and separate the BUILD_TOOLS_LANGTOOLS and os_linux.cpp failures. Done means identifying the build or environment cause and documenting the required project change or prerequisite.

Written by the indexing model from the issue text.