Makefile: Build man-page only when sphinx is available

Currently, it's not possible to compile the upstream branch using the
`make' command without sphinx beeing installed.

Check if sphinx-build is installed and only then build or install the
man-page.

The problem was noticed from commit
f4f2f3d move manpage to sphinx.

Change-Id: If1b81d9bc25ecac19d493b44b00a7c42d0643fe6
Signed-off-by: Thomas Heijligen <[email protected]>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/74519
Reviewed-by: Anastasia Klimchuk <[email protected]>
Tested-by: build bot (Jenkins) <[email protected]>

Makefile

@@ -36,6 +36,7 @@ EXPORTDIR ?= .
 RANLIB ?= ranlib
 PKG_CONFIG ?= pkg-config
 BUILD_DETAILS_FILE ?= build_details.txt
+SPHINXBUILD ?= sphinx-build
 
 # The following parameter changes the default programmer that will be used if there is no -p/--programmer
 # argument given when running flashrom. The predefined setting does not enable any default so that every
@@ -259,6 +260,7 @@ HAS_LINUX_MTD := $(call c_compile_test, Makefile.d/linux_mtd_test.c)
 HAS_LINUX_SPI := $(call c_compile_test, Makefile.d/linux_spi_test.c)
 HAS_LINUX_I2C := $(call c_compile_test, Makefile.d/linux_i2c_test.c)
 HAS_SERIAL := $(strip $(if $(filter $(TARGET_OS), DOS libpayload), no, yes))
+HAS_SPHINXBUILD := $(shell command -v $(SPHINXBUILD) &>/dev/null && echo yes || echo no)
 EXEC_SUFFIX := $(strip $(if $(filter $(TARGET_OS), DOS MinGW), .exe))
 
 override CFLAGS += -Iinclude
@@ -956,7 +958,7 @@ endif
 OBJS = $(CHIP_OBJS) $(PROGRAMMER_OBJS) $(LIB_OBJS)
 
 
-all: $(PROGRAM)$(EXEC_SUFFIX) man8/$(PROGRAM).8
+all: $(PROGRAM)$(EXEC_SUFFIX) $(call has_dependency, $(HAS_SPHINXBUILD), man8/$(PROGRAM).8)
 ifeq ($(ARCH), x86)
  @+$(MAKE) -C util/ich_descriptors_tool/ HOST_OS=$(HOST_OS) TARGET_OS=$(TARGET_OS)
 endif
@@ -1017,6 +1019,7 @@ config:
  echo "The following features are unavailable on your machine: $(UNSUPPORTED_FEATURES)" \
  exit 1; \
  fi
+ @echo "Checking for program \"sphinx-build\": $(HAS_SPHINXBUILD)"
 
 %.o: %.c | config
  $(CC) -MMD $(CFLAGS) $(CPPFLAGS) $(FLASHROM_CFLAGS) $(FEATURE_FLAGS) -D'FLASHROM_VERSION=$(VERSION)' -o $@ -c $<
@@ -1028,9 +1031,13 @@ libflashrom.a: $(OBJS)
  $(AR) rcs $@ $^
  $(RANLIB) $@
 
-SPHINXBUILD ?= sphinx-build
 man8/$(PROGRAM).8: doc/*
- @FLASHROM_VERSION=$(VERSION) $(SPHINXBUILD) -b man doc .
+ @if [ "$(HAS_SPHINXBUILD)" = "yes" ]; then \
+ $(SPHINXBUILD) -Drelease=$(VERSION) -b man doc .; \
+ else \
+ echo "$(SPHINXBUILD) not found. Can't build man-page"; \
+ exit 1; \
+ fi
 
 $(PROGRAM).bash: util/$(PROGRAM).bash-completion.tmpl
  @# Add to the bash completion file a list of enabled programmers.
@@ -1047,13 +1054,15 @@ clean:
  man8 .doctrees $(PROGRAM).bash $(BUILD_DETAILS_FILE)
  @+$(MAKE) -C util/ich_descriptors_tool/ clean
 
-install: $(PROGRAM)$(EXEC_SUFFIX) man8/$(PROGRAM).8 $(PROGRAM).bash
+install: $(PROGRAM)$(EXEC_SUFFIX) $(call has_dependency, $(HAS_SPHINXBUILD), man8/$(PROGRAM).8) $(PROGRAM).bash
  mkdir -p $(DESTDIR)$(PREFIX)/sbin
- mkdir -p $(DESTDIR)$(MANDIR)/man8
- mkdir -p $(DESTDIR)$(BASHCOMPDIR)
  $(INSTALL) -m 0755 $(PROGRAM)$(EXEC_SUFFIX) $(DESTDIR)$(PREFIX)/sbin
- $(INSTALL) -m 0644 man8/$(PROGRAM).8 $(DESTDIR)$(MANDIR)/man8
+ mkdir -p $(DESTDIR)$(BASHCOMPDIR)
  $(INSTALL) -m 0644 $(PROGRAM).bash $(DESTDIR)$(BASHCOMPDIR)
+ifeq ($(HAS_SPHINXBUILD), yes)
+ mkdir -p $(DESTDIR)$(MANDIR)/man8
+ $(INSTALL) -m 0644 man8/$(PROGRAM).8 $(DESTDIR)$(MANDIR)/man8
+endif
 
 libinstall: libflashrom.a include/libflashrom.h
  mkdir -p $(DESTDIR)$(PREFIX)/lib

Makefile.include

@@ -52,6 +52,10 @@ define dependency_version
 $(call debug_shell, $(if $(PKG_CONFIG_LIBDIR),PKG_CONFIG_LIBDIR=$(PKG_CONFIG_LIBDIR),) $(PKG_CONFIG) --modversion $1 2>/dev/null)
 endef
 
+define has_dependency # $1: dependency, $2: action/target
+$(if $(findstring $(strip $1),yes), $(strip $2))
+endef
+
 define dependency_cflags
 $(call debug_shell, $(if $(PKG_CONFIG_LIBDIR),PKG_CONFIG_LIBDIR=$(PKG_CONFIG_LIBDIR),) $(PKG_CONFIG) --cflags $1 2>/dev/null)
 endef