fix: Make HOST_MAP_MAX_ENTRIES configurable in host_map_test Makefile

- Add HOST_MAP_MAX_ENTRIES variable with default value 10
- Pass HOST_MAP_MAX_ENTRIES to both BPF and C compilation commands
- Enable the documented feature allowing users to customize map entries
  via 'make HOST_MAP_MAX_ENTRIES=N'

Signed-off-by: jingxuanxie <[email protected]>

Author: dr-xjx

example/gpu/host_map_test/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 OUTPUT := .output
 CLANG ?= clang
+HOST_MAP_MAX_ENTRIES ?= 10
 LIBBPF_SRC := $(abspath ../../../third_party/libbpf/src)
 BPFTOOL_SRC := $(abspath ../../../third_party/bpftool/src)
 LIBBPF_OBJ := $(abspath $(OUTPUT)/libbpf.a)
@@ -94,6 +95,7 @@ $(OUTPUT)/%.bpf.o: %.bpf.c $(LIBBPF_OBJ) $(wildcard %.h) $(VMLINUX) | $(OUTPUT)
 	$(call msg,BPF,$@)
 	$(Q)$(CLANG) -Xlinker --export-dynamic -g -O2 -target bpf -D__TARGET_ARCH_$(ARCH)		      \
 		     $(INCLUDES) $(CLANG_BPF_SYS_INCLUDES)		      \
+		     -DHOST_MAP_MAX_ENTRIES=$(HOST_MAP_MAX_ENTRIES)	      \
 		     -c $(filter %.c,$^) -o $(patsubst %.bpf.o,%.tmp.bpf.o,$@)
 	$(Q)$(BPFTOOL) gen object $@ $(patsubst %.bpf.o,%.tmp.bpf.o,$@)
 
@@ -107,7 +109,7 @@ $(patsubst %,$(OUTPUT)/%.o,$(APPS)): %.o: %.skel.h
 
 $(OUTPUT)/%.o: %.c $(wildcard %.h) | $(OUTPUT)
 	$(call msg,CC,$@)
-	$(Q)$(CC) $(CFLAGS) $(INCLUDES) -c $(filter %.c,$^) -o $@
+	$(Q)$(CC) $(CFLAGS) $(INCLUDES) -DHOST_MAP_MAX_ENTRIES=$(HOST_MAP_MAX_ENTRIES) -c $(filter %.c,$^) -o $@
 
 # Build application binary
 $(APPS): %: $(OUTPUT)/%.o $(LIBBPF_OBJ) | $(OUTPUT)