`make` doesn't work without first creating `build` subdirectory

[shitpoet]

I noticed small problem with Makefile: make doesn't work on Linux 64-bit (Debian) in latest version:

$ make
g++ -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/attack.cpp -o build/attack.o
g++ -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/bench.cpp -o build/bench.o
g++ -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/bitboard.cpp -o build/bitboard.o
g++ -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/board.cpp -o build/board.o
Assembler messages:
Fatal error: Assembler messages:
can't create build/attack.o: No such file or directoryFatal error:
can't create build/bitboard.o: No such file or directory
Assembler messages:
Fatal error: can't create build/board.o: No such file or directory
Assembler messages:
Fatal error: can't create build/bench.o: No such file or directory
make: *** [Makefile:67: build/attack.o] Error 2
make: *** Waiting for unfinished jobs....
make: *** [Makefile:67: build/bitboard.o] Error 2
make: *** [Makefile:67: build/bench.o] Error 2
make: *** [Makefile:67: build/board.o] Error 2

And in v1.0.0 tag version:

$ make
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/attack.cpp -o build/attack.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/bitboard.cpp -o build/bitboard.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/board.cpp -o build/board.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/book.cpp -o build/book.o
Assembler messages:
Fatal error: can't create build/bitboard.o: No such file or directory
Assembler messages:
Fatal error: can't create build/attack.o: No such file or directory
Assembler messages:
Fatal error: can't create build/book.o: No such file or directory
Assembler messages:
Fatal error: can't create build/board.o: No such file or directory
src/book.cpp:261:10: warning: ‘uint64_t {anonymous}::generate_poly_key(const board_t*)’ defined but not used [-Wunused-function]
  261 | uint64_t generate_poly_key(const board_t* board) {
      |          ^~~~~~~~~~~~~~~~~
make: *** [Makefile:67: build/book.o] Error 2
make: *** Waiting for unfinished jobs....
make: *** [Makefile:67: build/bitboard.o] Error 2
make: *** [Makefile:67: build/attack.o] Error 2
make: *** [Makefile:67: build/board.o] Error 2

But compiles after manually creating build subdirectory (v1.0.0 tag):

$ make
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/attack.cpp -o build/attack.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/bitboard.cpp -o build/bitboard.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/board.cpp -o build/board.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/book.cpp -o build/book.o
src/book.cpp:261:10: warning: ‘uint64_t {anonymous}::generate_poly_key(const board_t*)’ defined but not used [-Wunused-function]
  261 | uint64_t generate_poly_key(const board_t* board) {
      |          ^~~~~~~~~~~~~~~~~
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/eval.cpp -o build/eval.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/main.cpp -o build/main.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/movegen.cpp -o build/movegen.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/order.cpp -o build/order.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/rng.cpp -o build/rng.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/search.cpp -o build/search.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/see.cpp -o build/see.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/threads.cpp -o build/threads.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/time.cpp -o build/time.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/transposition.cpp -o build/transposition.o
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/tune.cpp -o build/tune.o
src/search.cpp:41:6: warning: ‘void {anonymous}::movcpy(move_t*, move_t*, int)’ defined but not used [-Wunused-function]
   41 | void movcpy(move_t *p_tgt, move_t *p_src, int n) {
      |      ^~~~~~
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto -c src/uci.cpp -o build/uci.o
src/time.cpp: In function ‘void calculate_movetime(searchinfo_t*)’:
src/time.cpp:25:39: warning: unused parameter ‘info’ [-Wunused-parameter]
   25 | void calculate_movetime(searchinfo_t *info) {
      |                         ~~~~~~~~~~~~~~^~~~
src/tune.cpp:155:8: warning: ‘double {anonymous}::sigmoid(double)’ defined but not used [-Wunused-function]
  155 | double sigmoid(double x) {
      |        ^~~~~~~
g++ -march=native -Wall -Wextra -Wpedantic -Wshadow -std=c++20 -mpopcnt -m64 -mbmi2 -Ofast -fno-exceptions -pipe -flto=auto build/attack.o build/bitboard.o build/board.o build/book.o build/eval.o build/main.o build/movegen.o build/order.o build/rng.o build/search.o build/see.o build/threads.o build/time.o build/transposition.o build/tune.o build/uci.o -o lishex