compilation of 8.0.0 FAILED: target/hexagon/idef-generated-emitter.indented.c on ubuntu 18.04
Description of problem:
Cannot compile on ubuntu 18.04.
Steps to reproduce:
1. get 8.0.0 tarball or git clone/submodule... on a ubuntu 18.04 system (with a few more recent tools in ~/opt, such as python 3.9)
2. ./configure --prefix=$HOME/opt && make
3. It finishes with this strange error: FAILED: target/hexagon/idef-generated-emitter.indented.c
```
...
[850/10154] Compiling C object target/hexagon/idef-parser.p/meson-generated_idef-parser.yy.c.o
[851/10154] Compiling C object target/hexagon/idef-parser.p/meson-generated_idef-parser.tab.c.o
[852/10154] Compiling C object target/hexagon/idef-parser.p/_home_pbourguignon_opt_src_qemu-8.0.0_target_hexagon_idef-parser_parser-helpers.c.o
[853/10154] Linking target target/hexagon/idef-parser
[854/10154] Generating target/hexagon/idef-generated-tcg with a custom command
[855/10154] Generating target/hexagon/indent with a custom command
FAILED: target/hexagon/idef-generated-emitter.indented.c
/home/pbourguignon/bin/indent -linux target/hexagon/idef-generated-emitter.c -o target/hexagon/idef-generated-emitter.indented.c
Indenting region...
Indenting region... done
Directory `/home/pbourguignon/opt/src/qemu-8.0.0/build/-linux target/hexagon/idef-generated-emitter.c -o target/hexagon/' does not exist; create? (y or n) Error reading from stdin
ninja: build stopped: subcommand failed.
Makefile:165: recipe for target 'run-ninja' failed
make[1]: *** [run-ninja] Error 1
make[1]: Leaving directory '/home/pbourguignon/opt/src/qemu-8.0.0/build'
GNUmakefile:10: recipe for target 'all' failed
make: *** [all] Error 2
```
Additional information:
https://dpaste.org/Hr9Zq
```
~/opt/src/qemu-git
16:15[pbourguignon@frprld7818008 :0.0 qemu-git ]$ ls ~/opt/bin
./	      ecl-config*     pydoc3@		 run-avr*      run-microblaze*
../	      emacs@	      pydoc3.9*		 run-bfin*     run-mips*
2to3@	      emacs-27.2*     python@		 run-bpf*      run-mn10300*
2to3-3.9*     emacsclient*    python3@		 run-cr16*     run-moxie*
bundle*       erb*	      python3-config@	 run-cris*     run-msp430*
bundler*      etags*	      python3.9*	 run-d10v*     run-or1k*
ccl*	      gcore*	      python3.9-config*  run-erc32*    run-ppc*
ccmake*       gdb*	      racc*		 run-frv*      run-pru*
cmake*	      gdb-add-index*  rake*		 run-ft32*     run-riscv*
cpack*	      gdbserver*      rbs*		 run-h8300*    run-rl78*
ctags*	      gem*	      rdbg*		 run-iq2000*   run-rx*
ctest*	      idle3@	      rdoc*		 run-lm32*     run-sh*
curl*	      idle3.9*	      ri*		 run-m32c*     run-v850*
curl-config*  irb*	      ruby*		 run-m32r*     sbcl*
ebrowse*      pip3*	      run-aarch64*	 run-m68hc11*  sis*
ecl*	      pip3.9*	      run-arm*		 run-mcore*    typeprof*
```