Make things depending on file extension - if-statement

Question

I try to make one thing or another depending if a file has extension p.md or md:
$(DST)/%.md.html: $(SRC)/%.md $(TMPHTML5)
$(eval EXT := $(suffix $<))
ifeq('$(EXT)','.p.md')
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F) -V otherformatspresentations=true
else
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F)
endif
but I get:
make site/ESPA4.Dia-0-presentacio.p.md.html -B
ifeq('.md','.p.md')
/bin/sh: -c: line 0: syntax error near unexpected token `'.md','.p.md''
/bin/sh: -c: line 0: `ifeq('.md','.p.md')'
make: *** [Makefile:103: site/ESPA4.Dia-0-presentacio.p.md.html] Error 1

Answer 1

Why don't you just use one pattern per type of file you want to create, as make was intended to be used?
$(DST)/%.p.md : $(SRC)/%.md $(TMPHTML5)
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F) -V otherformatspresentations=true
$(DST)/%.md : $(SRC)/%.md $(TMPHTML5)
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F)
Note that depending on which version of GNU make you're using order may or may not be important but this will work with all versions.
If you want to do it in one rule you can't use ifeq etc. That is a make command, and everything in the recipe is passed to the shell. The shell doesn't know anything about ifeq hence your errors. You'll have to either use the $(if ...) function or else use shell syntax completely:
$(DST)/%.md.html: $(SRC)/%.md $(TMPHTML5)
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F) $(if $(filter %.p.md,$<),-V otherformatspresentations=true)
Or:
$(DST)/%.md.html: $(SRC)/%.md $(TMPHTML5)
other=; case $< in (*.p.md) other="-V otherformatspresentations=true" ;; esac; \
$(PANDOC_MD_HTML) -o $# $< -V filename=$(<F) $$other